TN-1X

323-1061-100

SDH TRANSMISSION

Nortel TN-1X

System Description

Release 7 Standard (Revision 1) November 1997

Nortel TN-1X System Description

SDH TRANSMISSION

Nortel TN-1X

System Description

Document Number: 323-1061-100Document Status: Standard (Revision 1)Product Release Number: Release 7Date: November 1997

Copyright

1995, 1996, 1997 Northern Telecom

Printed in England

The copyright of this document is the property of Northern Telecom. Without the written consent of Northern Telecom, given by contract or otherwise, this document must not be copied, reprinted or reproduced in any material form, either wholly or in part, and the contents of this document, or any methods or techniques available therefrom, must not be disclosed to any other person whatsoever.

NORTHERN TELECOM CONFIDENTIAL:

The information contained in this document is the property of Northern Telecom. Except as specifically authorized in writing by Northern Telecom, the holder of this document shall keep the information contained herein confidential and shall protect same in whole or in part from disclosure and dissemination to third parties and use same for evaluation, operation and maintenance purposes only.

So far as Northern Telecom is aware the contents of this document are correct. However, such contents have been obtained from a variety of sources and Northern Telecom can give no warranty or undertaking and make no representation as to their accuracy. In particular, Northern Telecom hereby expressly excludes liability for any form of consequential, indirect or special loss, and for loss of data, loss of profits or loss of business opportunity, howsoever arising and whether sustained by the user of the information herein or any third party arising out of the contents of this document.

iii

Publication historyNovember 1997

Release 7 Standard (Revision 1).

October 1997Release 7 Standard.

November 1996Release 6 Standard.

December 1995Release 5.1 Standard.


v

ContentsAbout this document xiii

Technical support and information xiv

Introduction to Nortel’s SDH transmission range 1-1New standard for optical transport 1-1Nortel’s SDH transmission equipment 1-2Transport equipment 1-3

TN-1X network element 1-3TN-1P network element 1-3TN-1C network element 1-4TN-4X network element 1-4TN-16X network element 1-5TN-X/40 SDH Radio network element 1-6

System overview 2-1Nortel TN-1X network element 2-1TN-MS Element Controller for TN-1 2-4

Standby Element Controller 2-4Network Resource Manager 2-5

System configurations 2-5Terminal multiplexer 2-7Drop and insert multiplexer 2-7STM-4 aggregates 2-9STM-1 tributaries 2-11

Connectivity 2-13Channel numbering schemes 2-13Port/channel designations 2-13

Connection types 2-16Internal traffic connections 2-17Traffic connections 2-18Standby connections 2-19User labels 2-20

Engineering Order Wire 2-20

Equipment description 3-1Equipment 3-1

TN-1X subrack 3-1TN-1X/S subrack 3-1Subrack layouts 3-3Variants 3-3Plug-in units 3-5


vi

Interface modules 3-8Connector panels 3-10Local Craft Access Panel 3-10

VC-12/VC-3 path protection switching 3-11Modes of operation 3-11Persistence checks 3-12STM-1 tributaries 3-12

N+1 2 Mbit/s tributary protection 3-13Modes of operation 3-14Switching prerequisites 3-14N+1 tributary switching alarms 3-15

Payload Manager switching 3-15Switching prerequisites 3-16

Loopback 3-162 Mbit/s Tributary Unit 3-17STM-1 Aggregate Unit/STM-1 Tributary Unit 3-1834 Mbit/s Tributary Unit 3-18

Single fibre working 3-19Automatic laser shutdown 3-20

Laser test facility 3-22Engineering Order Wire operation 3-23Construction 3-23

Plug-in units 3-29Interface modules 3-29EOW handset 3-30Electro-Magnetic Compatibility protection 3-31Electro Static Discharge protection 3-31Earthing arrangements 3-32Unused subrack positions 3-32

Thermal qualifications 3-32Initialisation 3-33

Initial power-up sequence 3-33Configuration 3-34

Traffic processing 4-1Internal traffic interfaces 4-1

Tributary Unit/Payload Manager interfaces 4-2Payload Manager/Aggregate Unit interfaces 4-3Overhead buses 4-4

Traffic processing 4-42 Mbit/s Tributary Unit 4-934 Mbit/s Tributary Unit 4-9STM-1 Tributary Unit 4-10Payload Manager 4-12STM-1 Aggregate Unit 4-13STM-4 Optical Aggregate Unit 4-14

Equipment management 5-1Backplane interfaces 5-1Subrack Controller 5-3Card controllers 5-3Real time clock 5-4

Alarm monitoring 5-5Alarm handling 5-5

323-1061-100 Release 7 Standard (Revision 1)

vii

External alarms 5-6Performance monitoring 5-8Path trace (J1 byte) 5-13

Single fibre working 5-14Signal label (C2 and V5 bytes) 5-14Software 5-15

Software upgrade overview 5-16Software status 5-17

Configuration data 5-19Configuration table status 5-19Detached mode 5-20

Inventory 5-21Local terminal interface 5-21Network management 5-22

Remote Layer Management 5-24Third-party router interoperability 5-26

Power and synchronisation 6-1Power 6-1

Power supply to the TN-1X subracks 6-1Synchronisation 6-4

Synchronisation sources 6-4Synchronisation source hierarchy 6-5Synchronisation settings 6-5Synchronisation switching mechanisms 6-6Synchronisation status messaging 6-6Synchronisation status messaging network examples 6-8Inter-operating with non-SSM networks 6-10SSM recommendations 6-11Non-SSM synchronisation sourcing 6-12Failure of synchronisation source 6-13External synchronisation output 6-14Synchronisation alarms 6-14

System parameters 7-1Operating parameters 7-1

Power requirements 7-1Construction 7-1System interfaces 7-3ElectroMagnetic compatibility 7-7Environmental conditions 7-7

External interfaces 8-1Introduction 8-1Local Craft Access Panel 75 Ω 8-2

Mating connectors/cabling 8-375 Ω Traffic Access Module (TN-1X) 8-4

Mating connectors/cabling 8-575 Ω Traffic Access Module (N+1 Protection) (TN-1X) 8-6

Mating connectors/cabling 8-775 Ω Traffic Access Module (TN-1X/S) 8-8

Mating connectors/cabling 8-9120 Ω Traffic Access Module (TN-1X) 8-10

Mating connectors/cabling 8-12


viii

120 Ω Traffic Access Module (N+1 Protection) (TN-1X) 8-13Mating connectors/cabling 8-15

120 Ω Traffic Access Module (TN-1X/S) 8-16Mating connectors/cabling 8-18

High Speed Traffic Access Module 8-19Mating connectors/cabling 8-20

High Speed Aggregate Module 8-21Mating connectors/cabling 8-22

High Speed Tributary Module 8-23Mating connectors/cabling 8-24

Station Service Module 8-25Mating connectors/cabling 8-27

75 Ω Star Card 8-28Mating connectors/cabling 8-29

Flexible Termination Module 8-30Flexible Access Module 8-31

Mating connectors/cabling 8-32Power & LCAP Module 8-33

Mating connectors/cabling 8-35Flexible Access Module (External Alarms) 8-36

Mating connectors/cabling 8-37External Alarm Module 8-38

Mating connectors/cabling 8-3975 Ω Connector Panel 8-40

Mating connectors/cabling 8-40120 Ω Connector Panel 8-41

Mating connectors/cabling 8-42EOW/CATT Connector Panel 8-43

Mating connectors/cabling 8-44Cabling and connector arrangements 8-45

TN-1X subrack 8-45TN-1X/S subrack 8-45Optical connections 8-49LAN connections 8-50

Equipment codes 9-1Unit codes 9-1TN-1X subrack codes 9-3TN-1X/S subrack codes 9-3Blank panel codes 9-3

Appendix A: Synchronous digital hierarchy 10-1SDH multiplexing structure 10-2Nortel TN-1X 10-4Mapping of a 2048 kbit/s signal into a VC-12 10-4Mapping of a 34368 kbit/s signal into a VC-3 10-5Multiplexing of VC-12s into a TUG-2 10-6Multiplexing of TUG-2s into a TUG-3 10-8Multiplexing of a VC-3 into a TUG-3 10-8Mapping of TUG-3s into a VC-4 10-8Mapping of a VC-4 into a STM-1 via an AU-4/AUG 10-9Path overheads 10-10Section overhead 10-11Nortel TN-1X/4 10-12


ix

Important notes 11-1Introduction 11-1Operational qualifications for Release 7 TN-1X multiplexer 11-1

Index 12-1

FiguresFigure 1-1 SDH networking 1-2Figure 1-2 TN-1X network element 1-3Figure 1-3 TN-1P network element 1-3Figure 1-4 TN-1C network element 1-4Figure 1-5 TN-4X network element 1-4Figure 1-6 TN-16X network element 1-5Figure 2-1 Nortel TN-1X - external interfaces 2-2Figure 2-2 Nortel TN-1X - typical system 2-6Figure 2-3 Terminal multiplexer 2-7Figure 2-4 Drop and insert multiplexer chains 2-8Figure 2-5 Drop and insert multiplexer ring 2-9Figure 2-6 TN-1X/4 multiplexer - STM-1 routing 2-10Figure 2-7 Typical deployment of the TN-1X/4 in an STM-4 access ring 2-11Figure 2-8 STM-1 tributary configurations 2-12Figure 2-9 TN-1X connection types 2-16Figure 3-1 Nortel TN-1X - block diagram 3-2Figure 3-2 Nortel TN-1X/S - block diagram 3-3Figure 3-3 Nortel TN-1X - subrack layout 3-4Figure 3-4 Nortel TN-1X/S - subrack layout 3-5Figure 3-5 Position of loopbacks 3-17Figure 3-6 Nortel TN-1X - single fibre operation 3-19Figure 3-7 Automatic laser shutdown operation 3-21Figure 3-8 TN-1X unequipped subrack 3-24Figure 3-9 TN-1X/S unequipped subrack 3-24Figure 3-10 TN-1X subrack backplane - plug-in unit area 3-26Figure 3-11 TN-1X subrack backplane - station interface area 3-27Figure 3-12 TN-1X/S subrack backplane 3-28Figure 3-13 Station interface area cover 3-30Figure 3-14 EOW handset - TN-1X mounting position 3-31Figure 4-1 Inter-unit traffic connections 4-2Figure 4-2 Trib Unit/Payload Manager packed TU (secondary) format 4-3Figure 4-3 Payload Manager/Aggregate Unit floating AU (primary) format 4-3Figure 4-4 Nortel TN-1X traffic processing (2 Mbit/s tributaries) 4-5Figure 4-5 Nortel TN-1X traffic processing (34 Mbit/s tributaries) 4-6Figure 4-6 Nortel TN-1X/4 traffic processing (STM-1 tributaries) 4-7Figure 4-7 Nortel TN-1X traffic processing (mixed payloads) 4-8Figure 5-1 Equipment management bus architecture 5-2Figure 5-2 Software upgrade overview 5-18Figure 5-3 General network management architecture 5-23Figure 6-1 Typical TN-1X rack power cabling and fusing 6-3Figure 6-2 Synchronisation source - block diagram 6-4Figure 6-3 SSM within a simple STM-N ring with a single external source 6-8Figure 6-4 SSM within a simple STM-N ring with two external sources 6-9Figure 6-5 SSM within a simple STM-N ring with two external sources 6-10Figure 6-6 SSM in STM-N ring inter-connecting with non-SSM network 6-11Figure 8-1 Local Craft Access Panel 75 Ω - front view 8-2Figure 8-2 75 Ω TAM (TN-1X) - front and side views 8-4


x

Figure 8-3 75 Ω TAM (TN-1X) - 2 Mbit/s port allocation 8-5Figure 8-4 75 Ω TAM (N+1 Protection) (TN-1X) - front and side views 8-6Figure 8-5 75 Ω TAM (N+1 Protection) (TN-1X) - 2 Mbit/s port allocation 8-7Figure 8-6 75 Ω TAM (TN-1X/S) - front and side views 8-8Figure 8-7 75 W TAM (TN-1X/S) - 2 Mbit/s port allocation 8-9Figure 8-8 120 Ω TAM (TN-1X) - front and side views 8-10Figure 8-9 120 Ω TAM (TN-1X) - 2 Mbit/s port allocation 8-11Figure 8-10 120 Ω TAM (N+1 Prot’n) (TN-1X) - front and side views 8-13Figure 8-11 120 Ω TAM (N+1 Prot’n) (TN-1X) - 2 Mbit/s port allocation 8-14Figure 8-12 120 Ω TAM (TN-1X/S) - front and side views 8-16Figure 8-13 120 Ω TAM (TN-1X/S) - 2 Mbit/s port allocation 8-17Figure 8-14 High Speed TAM - front and side views 8-19Figure 8-15 High Speed Aggregate Module - front and side views 8-21Figure 8-16 High Speed Tributary Module - front and side views 8-23Figure 8-17 Station Service Module - front and side views 8-25Figure 8-18 75 Ω Star Card - front and side views 8-28Figure 8-19 Flexible Termination Module - front and side views 8-30Figure 8-20 Flexible Access Module - front and side views 8-31Figure 8-21 Power & LCAP Module - front and side views 8-33Figure 8-22 Power & LCAP Module - earth strapping pins 8-34Figure 8-23 Flexible Access Module (Ext Alarms) - front and side views 8-36Figure 8-24 External Alarms Module - front and side views 8-38Figure 8-25 75 Ω Connector Panel 8-40Figure 8-26 75 Ω Connector Panel - suggested port connections 8-40Figure 8-27 120 Ω Connector Panel 8-41Figure 8-28 120 Ω Connector Panel - connector pin allocation 8-41Figure 8-29 120 Ω Connector Panel - suggested port connections 8-42Figure 8-30 EOW/CATT Connector Panel - front view 8-43Figure 8-31 TN-1X 75 Ω traffic cable grooming 8-46Figure 8-32 TN-1X 120 Ω traffic cable grooming 8-47Figure 8-33 TN-1X/S 75 Ω traffic cable grooming 8-48Figure 8-34 TN-1X/S 120 Ω traffic cable grooming 8-48Figure 8-35 Connector panel forward and rearward positions 8-49Figure 10-1 SDH generalised multiplexing structure 10-2Figure 10-2 STM-1 frame structure 10-4Figure 10-3 Nortel TN-1X - multiplexing structure 10-4Figure 10-4 2048 kbit/s tributary/VC-12/TU-12 mapping 10-5Figure 10-5 34368 kbit/s tributary/VC-3 mapping 10-6Figure 10-6 Multiplexing of TU-12 via a TUG-2 10-7Figure 10-7 TU-12/TUG-2/TUG-3 multiplexing 10-7Figure 10-8 Multiplexing of a TU-3 via a TUG-3 10-8Figure 10-9 Multiplexing of three TUG-3s into a VC-4 10-9Figure 10-10 Mapping of a VC-4 into a STM-1 via an AU-4/AUG 10-9Figure 10-11 VC-12 Path Overhead 10-10Figure 10-12 Section overhead 10-11Figure 10-13 STM-4 frame structure 10-12Figure 10-14 STM-4 section overhead 10-13

TablesTable 1-1 SDH line rates 1-1Table 2-1 Channel numbering schemes 2-14Table 5-1 Performance monitoring points (PMPs) and error counts 5-10Table 5-2 PMP anomalies and defects 5-11Table 6-1 QL settings for use with SSM 6-7Table 8-1 Local Craft Access Panel 75 Ω - connector pin-out 8-2


xi

Table 8-2 Station Service Module - rack alarm connector pin-out 8-26Table 8-3 Station Service Module - LAN connector pin-out 8-26Table 8-4 Station Service Module - power connector pin-out 8-26Table 8-5 Station Service Module - earth strapping options 8-27Table 8-6 Power & LCAP Module - power connector pin-out 8-33Table 8-7 Power & LCAP Module- earth strapping options 8-34Table 8-8 Power & LCAP Module - EOW/CATT connector pin-out 8-35Table 8-9 Flexible Access Module - external alarm connector pin-out 8-37Table 8-10 External Alarm Module - external alarm connector pin-out 8-38Table 8-11 EOW/CATT Connector Panel - connector pin-out 8-43Table 9-1 Plug-in unit codes 9-1Table 9-2 TN-1X Interface Module codes 9-2Table 9-3 TN-1X/S Interface Module codes 9-3Table 9-4 Connector Panel codes 9-3


xiii

About this documentThis document provides a system level description of the Nortel TN-1X multiplexer. The document acts as a concise introduction to the equipment and is recommended for anyone working with the TN-1X.

The document is divided in a number of chapters which describe different aspects of the Nortel TN-1X as follows:

• Chapter 1: Provides an introduction to the Nortel’s SDH transmission range of products and the Synchronous Digital Hierarchy (SDH).

• Chapter 2: Provides a system overview of the Nortel TN-1X multiplexer including system configurations.

• Chapter 3: Provides a description of the Nortel TN-1X units and features.

• Chapter 4: Provides information on the Nortel TN-1X traffic processing.

• Chapter 5: Provides information on the Nortel TN-1X equipment management including alarm handling and performance monitoring.

• Chapter 6: Provides information on the Nortel TN-1X power and synchronisation functions.

• Chapter 7: Provides performance specifications for the Nortel TN-1X including system interfaces and optical power budgets.

• Chapter 8: Provides details of the Interface Modules and Connector Panels which provide the external connectors for the Nortel TN-1X multiplexers.

• Chapter 9: Provides coding and ordering information for the Nortel TN-1X units.

• Appendix A: Provides an introduction to the Synchronous Digital Hierarchy (SDH).

• Appendix B: Important notes.


xiv

Technical support and informationNortel provides a comprehensive technical support service for its customers. The Nortel Service Desk may be contacted Monday to Friday between the hours of 08:30 and 17:00 (UK local time), using the following FAX or telephone numbers:

United KingdomFreephone: 0800 626 881Telephone: 0181 361 4693FAX: 0181 945 3456

InternationalTelephone: +44 181 361 4693FAX: +44 181 945 3456

Access to assistance from the Customer Service Desk 24 hour help line can be provided and is subject to a suitable Support Agreement being in place.

To discuss Technical Support services, please contact the Technical Support Hotline on 0181 945 3525.

Declaration of product safety and EMC compliance

This product/product family complies with the provisions of the Low Voltage Directive 73/23/EEC, and with the essential protection requirements of the EMC Directive 89/336/EEC as amended by 92/31/EEC, when it is properly installed and maintained and when it is used for the purposes for which it is intended.


1-1

1

Introduction to Nortel’s SDH transmission range 1-

This chapter describes the Nortel’s SDH transmission equipment family which includes the Nortel TN-1C, TN-1P, TN-1X, TN-4X and TN-16X network elements, and the Nortel TN-X/40 SDH Radio network element. Appendix A provides details of the Synchronous Digital Hierarchy (SDH) for readers who are not familiar with the SDH standard.

New standard for optical transportSDH is the acronym for Synchronous Digital Hierarchy and is the standard for traffic transport formulated by the International Telecommunications Union - Telecommunications Standardisation Section (ITU-T), formally the International Telegraph and Telephone Consultative Committee (CCITT).

Some of the benefits of SDH are:

• multi-vendor environment (mid-span meet)

• synchronous networking

• enhanced operations, administration, maintenance, and provisioning (OAM&P)

• positioning the network for transport of new services

SDH defines the Synchronous Transport Module (STM) signal levels. The base rate is 155.520 Mbit/s. Higher rates are direct integer multiples of the base rate. The SDH line rates are illustrated in Table 1-1.

Table 1-1SDH line rates

STM Level Line rate (Mbit/s)

STM-1 155.520

STM-4 622.080

STM-16 2488.320

STM-64 9953.28


1-2

Introduction to Nortel’s SDH transmission range

SDH defines a physical layer, which is the photonic layer, required to interconnect equipment from different vendors. This is based on the Open Systems Interconnection (OSI) seven-layer model for data communications. Efforts are currently under way to define the upper layers.

Note: The higher line rates are integer multiples of the base rate of 155.520 Mbit/s. For example, STM-16 = 16 x 155.52 Mbit/s = 2488.320 Mbit/s.

Nortel’s SDH transmission equipmentNortel’s family of SDH-based products are designed to meet the evolving needs of the telecommunications industry. Nortel’s SDH products encompass optical, electrical and radio transmission systems, digital switches, and cross-connects and comprise:

• SDH and radio products designed for high-capacity transport applications.

• Fibre products designed for multi-service access applications.

• A digital switch developed for the new generation of switching products.

When deployed together, the SDH family can provide a single synchronous network, as shown in Figure 1-1.

Figure 1-1SDH networking

Transport

Switching Access

STM-1/STM-4

STM-1/STM-4

STM-1/STM-4STM-16

SDHRadio

STM-1/STM-4STM-16

equipment

equipment equipment

Accessequipment


Introduction to Nortel’s SDH transmission range

1-3

1

Transport equipmentThe transport equipment provides for today’s increasing demand for new broadband services and high-capacity systems. In view of these needs, as well as the need for multi-vendor interconnecting, the transport equipment has been developed for full SDH compliance. It addresses the trend toward future SDH networking.

The transport equipment consists of several network elements (NEs), which are used for high-capacity transport. Each NE is described below. Together, these transport products can be deployed in various network applications.

TN-1X network elementThe TN-1X NE (see Figure 1-2) provides 2 Mbit/s to 155 Mbit/s terminal multiplexing, add/drop, ring and cross-connectivity features. Optical and electrical STM-1 tributaries may be employed for the provision of STM-1 spurs to customer sites or for interconnection of clusters of multiplexers. This multiplexer also supports an STM-4 aggregate capability, as well as a range of plesiochronous tributary interfaces.

Figure 1-2TN-1X network element

TN-1P network elementThe TN-1P NE (see Figure 1-3) provides terminal multiplexing for up to four 2 Mbit/s (75 Ω or 120 Ω) electrical tributaries into an STM-1 optical signal. TN-1Ps may be employed in point-to-point connections with a TN-1P at each end, or as a spur onto a SDH network.

Figure 1-3TN-1P network element

TN-1Xnetworkelement

STM-1orSTM-4

2 Mbit/s,34 Mbit/s,

STM-1

TN-1Pnetworkelement

STM-12 Mbit/s


1-4 Introduction to Nortel’s SDH transmission range

TN-1C network elementThe TN-1C NE (see Figure 1-4) provides add/drop multiplexing for up to sixteen 2 Mbit/s (75 Ω or 120 Ω) electrical tributaries, or up to eight 2 Mbit/s (75 Ω or 120 Ω) electrical tributaries and a 34/45 Mbit/s (VC-3) electrical tributary, into an STM-1 optical signal. TN-1Cs may be employed in ring configurations, point-to-point configurations, or as a spur onto a SDH network.

Figure 1-4TN-1C network element

TN-4X network elementThe TN-4X Network Element is an STM-4 multiplexer for use as a ring head in STM-4 local network rings, or as an STM-4 ring node in core network applications. The TN-4X can also be configured as a low capacity cross-connect for use primarily at the local/regional network boundary.

The TN-4X supports a wide range of plesiochronous and synchronous interfaces as shown in Figure 1-5.


TN-1Cnetworkelement

STM-12 Mbit/s

34/45 Mbit/s

STM-1e

Port Cards34 Mbit/s

140 Mbit/s

2 Mbit/sSTM-4

STM-1e

34 Mbit/s

140 Mbit/s

SwitchUnits


Introduction to Nortel’s SDH transmission range 1-5

1
TN-16X network elementThe TN-16X (STM-16) NE (see Figure 1-6) transports up to 16 STM-1 signals. These signals are provided by tributaries, which can be a mix of a number of signal types.
There can be up to:

• four 3 x 34 Mbit/s tributaries

• thirty-two 1+1 protected STM-1o tributaries

• sixteen STM-1e or STM-1e/140 M tributaries

• eight 1+1 protected STM-4o tributaries

or a mixture of types (note that you cannot mix STM-4o tributaries with any other type within the same quadrant). The signals are multiplexed, and converted into the SDH STM-16 optical format for transmission over singlemode fibre.

There are two basic network topologies available: a linear and a ring topology.

• The linear topology provides point-to-point transport between two TN-16X terminal shelves. TN-16X regenerator/optical amplifier shelves can be used to extend the distance limits of the fibre-optic line between the terminal shelves.

• The MS SPRing ring topology provides full survivability in the event of the loss of a fibre-optic line or any of the nodes in the ring. In the ring topology, each TN-16X Terminal shelf is configured as an add-drop multiplexer (ADM) node. The ADM nodes can add and drop definable numbers of STM-1 or 140 Mbit/s signals as well as pass signals through to adjacent nodes. The ring topology can also use regenerator/optical amplifiers between ADM nodes.

TN-16X terminals and ADM nodes can be interconnected by way of tributaries. Supported tributary types (34 Mbit/s, STM-1e, STM-1o, STM-4o) can be used in connections between rings.


TN-16Xnetworkelement

STM-1634 Mbit/sSTM-1

or 140 Mbit/sor STM-4o


1-6 Introduction to Nortel’s SDH transmission range

TN-X/40 SDH Radio network element Nortel’s product range includes a variety of SDH radio systems offering STM-1 and higher capacities at various frequencies. The radio systems are used to provide ring closure in the Regional and Local network.

end of chapter


2-12

System overview 2-This chapter provides a system overview of the Nortel TN-1X multiplexer and details the different system configurations.

Nortel TN-1X network elementThere are two versions of the TN-1X, the full-height version (TN-1X) and a reduced-height version (TN-1X/S).

Note: Unless there are specific differences, the designation TN-1X is used to refer to the TN-1X and the TN-1X/S.

The equipment provides multiplexing between the following tributary and aggregate ports:

• tributaries. It is possible to mix the following tributary types up to a maximum capacity of sixty-three Tributary Unit-12s (TU-12s).

— 2048 kbit/s electrical ports

– up to sixty-three 2048 kbit/s electrical ports (TN-1X)

– up to sixteen 2048 kbit/s electrical ports (TN-1X/S)

— 34368 kbit/s electrical ports

– up to four 34368 kbit/s electrical ports (TN-1X), each port providing access to sixteen 2048 kbit/s signals

— STM-1 tributary ports

– up to four STM-1 optical or electrical tributary ports (TN-1X)

– up to four STM-1 optical tributary ports (TN-1X/S)

• aggregates. It is possible to mix the following aggregate ports up to a maximum of two.

— STM-1 aggregate ports

– one or two STM-1 optical or electrical aggregate ports (TN-1X)

– one or two STM-1 optical aggregate ports (TN-1X/S)

— STM-4 aggregate ports

– one or two STM-4 optical aggregate ports (TN-1X and TN-1X/S). A multiplexer fitted with two STM-4 ports is referred to as TN-1X/4.


2-2 System overview

Figure 2-1 shows the external interfaces associated with the Nortel TN-1X and the TN-1X/S multiplexers.

Figure 2-1Nortel TN-1X - external interfaces

The equipment is designed to operate in a managed network environment, however, it is capable of being used in a stand alone mode where a network management infrastructure does not exist.

Port BPort A

Port BPort A

Rack Alarm Bus

Local TerminalInterface

STM-N Aggregate Ports

Power

Synchronisation Input/Output

2048 kbit/sElectrical Ports

Nortel TN-1X

1 63

NetworkManagementInterface

STM-1Tributary Ports

1 4

External Alarms

Nortel TN-1X

Local TerminalInterface

STM-N Aggregate Ports

Power

2048 kbit/sElectrical Ports

NortelTN-1X/S

1 16STM-1

Tributary Ports

1 4

External Alarms

Nortel TN-1X/S

EOW

EOW

1 434368 kbit/s

Electrical Ports


System overview 2-3

2

The TN-1X is managed using application software embedded on the TN-1X which performs the internal control and monitoring functions. The configuration and status information is stored in each network element and not in the management tools used to control them. Refer to Chapter 5 ‘Equipment management’ for more information.

The TN-1X can be monitored and configured by accessing the User Interface (UI) of the application software. The UI can be accessed either:

• locally by a Craft Access Terminal (CAT) connected directly to the TN-1X

• remotely via the TN-MS Element Controller (EC).

Note: The TN-1X also provides an interface to the rack alarm system (not applicable to the TN-1X/S).

Two types of UI are made available:

• Browser User Interface (Browser). This is a point-and-click hypertext interface. The interface is viewed by Netscape Navigator™. For more information on the Browser, refer to the TN-1X Browser User Interface Guide, NTP 323-1061-403.

• Command Line User Interface. This is a text-based interface. For more information on the Command Line User Interface, refer to the TN-1X Command Line User Interface Guide, NTP 323-1061-401.

When used in a managed network environment, the TN-1X multiplexer operates as either:

• a ‘gateway network element’ (TN-1X only) which provides an interface to the next layer of the network management hierarchy (e.g. element controller) and an interface for remote multiplexers via the Embedded Control Channel (ECC).

• a ‘network element’ (TN-1X and TN-1X/S) which provides an interface to the next layer of the network management hierarchy, or interfaces via the ECC and a ‘gateway network element’.

The ECC is provided by the section overhead in the STM-1 or STM-4 frame structure.


2-4 System overview

TN-MS Element Controller for TN-1 The TN-MS Element Controller for TN-1 (TN-MS EC-1) is a complete network management application software package, operating at the Element Manager level of the network management hierarchy. The system can be run on a single Hewlett Packard UNIX workstation, and uses a Graphical User Interface (GUI) to provide flexible management of Nortel TN-1X, TN-1X/S, TN-1C and TN-1P multiplexers. Details of the TN-MS Element Controller are provided in TN-MS Element Controller for TN-1 User Procedures, NTP 323-1061-402.

The Element Controller facilities are divided into five main areas:

• Configuration: This function provides the means of adding, copying, modifying, and removing network elements. The Element Controller provides GUI sessions for configuration and connection management, and also provides access to the UI on the NE for further configuration facilities.

• Alarm/Event Monitoring: Events (changes in status of network entities) and alarms (indications of actual or potential failures) are received as unsolicited reports from the network elements. The Element Controller provides on-screen displays at three different levels of detail (including an Alarm Count only mode), and full event logging and reporting facilities.

• Performance Monitoring: The TN-1X, TN-1X/S, TN-1C and TN-1P NEs have comprehensive performance monitoring facilities, allowing the monitoring of selected points within the multiplexer against a range of performance criteria. The Element Controller uses these facilities to provide powerful report generation features.

• Security Management: The Element Controller provides security safeguards against unauthorised users, and restricts authorised users to a subset of features appropriate to their role. Data security is provided by automatic daily back-ups of all network data and clear warnings are provided if the system disk becomes too full.

• Reporting: The reporting function of the Element Controller allows the generation of reports about event logs, performance logs, NE configuration, and faulty equipment.

Standby Element ControllerIn the event of a major failure of the principal Element Controller, whereby recovery is not possible within an acceptable time-span, a standby Element Controller may be brought into operation to manage the network.

Where a cold standby Element Controller is used, the principal and standby EC-1s are connected via a LAN/WAN. Selection of a Element Controller as a principal or standby platform is performed during installation.


System overview 2-5

2

Network Resource ManagerThe TN-MS EC-1 is capable of providing an interface to the Network Resource Manager (NRM). The NRM is a software application which runs on a Hewlett-Packard UNIX workstation, complementing and adding value to the functions provided by TN-MS Element Controllers. It provides a graphical representation of the network and of any alarms collected from the network elements in it. Communication with the system is provided on-screen, via dialogue boxes and menus.

Network Resource Manager provides a single point of access to the existing operations, administration, and maintenance, and provisioning (OAM&P) functions in a network. This includes:

• Connection management.

• Consolidation of performance monitoring data from multiple Element Controllers and across different NE types.

• Hierarchical displays, background maps, and partitioned user views.

System configurationsThe TN-1X can be configured to operate as:

• A conventional terminal multiplexer fitted with two aggregate units for use in protected point to point configurations. The two aggregate ports, A and B, are used in a main/standby mode to provide 1 for 1 protection for the aggregate ports.

• A drop and insert multiplexer fitted with two aggregate units whereby the two aggregate ports, A and B, provide ‘East’ and ‘West’ ports for connection in drop and insert rings or chains. When connected in a drop and insert ring, protection of the traffic can be provided by alternative routing around the ring, this is not possible when configured in a drop and insert chain.

• A terminal multiplexer fitted with a single aggregate unit for use in unprotected point to point systems, or as end terminals in a drop and insert chain.

The different configurations for the TN-1X (i.e. terminal multiplexer, drop and insert ring, and drop and insert chain) are shown in Figure 2-2.


2-6 System overview

Figure 2-2Nortel TN-1X - typical system

STM-1

2 Mbit/s

Main

Standby

(A) Point to point subsystem

(B) Ring subsystem

Possible routing to provide flattened ring

(C) Drop & insert chain subsystem

ElementController

ManagementLAN

STM-1

STM-1

STM-1

STM-1 STM-1STM-1

STM-1

STM-1

STM-1

STM-1STM-1STM-1STM-1 STM-1

STM-1

2 Mbit/s

2 Mbit/s

2 Mbit/s

2 Mbit/s

2 Mbit/s 2 Mbit/s 2 Mbit/s

STM-1Trib

2 Mbit/s

STM-1 STM-1

2 Mbit/s

STM-1

2 Mbit/s

STM-1 Link(Spur)

LAN

I/F

LAN

I/F

LAN I/F

K TN-1X multiplexers must be used in the positionsmarked K, as the TN-1X/S does not have a LAN port.

K

K

K


System overview 2-7

2

Terminal multiplexerWhen configured as a conventional terminal multiplexer with two aggregate units, the Nortel TN-1X provides a point-to-point link with inherent 1 for 1 protection (see Figure 2-3).

Figure 2-3Terminal multiplexer

The 1 for 1 protected terminal multiplexer configuration can be achieved by configuring the multiplexer as a drop and insert multiplexer and setting all 63 tributaries as protected connections.

An unprotected terminal multiplexer configuration can be achieved by configuring the multiplexer as a drop and insert multiplexer, setting all 63 tributaries as unprotected connections to one aggregate port, and unequipping the unused aggregate port.

Drop and insert multiplexerWhen configured as a drop and insert multiplexer (also known as an Add/Drop Multiplexer), the Nortel TN-1X can be used in two configurations:

• drop and insert chain

• drop and insert ring

Figure 2-4 shows examples of drop and insert chains.

When using a simple drop and insert chain as shown in Figure 2-4(a), no protection is provided against faults in the optical path and the multiplexers are configured as unprotected. In this configuration, the end terminals only require a single aggregate port (i.e. unprotected terminal multiplexers as described in the previous section).

Flattened rings (see Figure 2-4(b)) make use of existing patterns of ducts and fibres to form a distorted ring. Protection against faults in the optical paths is provided by routing the traffic simultaneously both ways around the ring and configuring the multiplexers as drop and insert multiplexers. However, the flattened ring configuration is susceptible to the common mode faults (e.g. both optical fibres in a duct being broken at the same time).

TN-1X TN-X TributariesTributaries

A A

BB

Main

Standby


2-8 System overview

Figure 2-4Drop and insert multiplexer chains

Figure 2-5 shows an example of a drop and insert ring.

The drop and insert ring provides diverse routing which overcomes common mode faults and thus provides protection against a fault in any optical path. Tributaries that require protection (e.g. Private Circuit (PC) traffic) are routed both ways around the ring. At the receiving multiplexer, traffic from the ‘A’ port (default selection) is used unless there is a fault (see “VC-12/VC-3 path protection switching” on page 3-11 for details) when traffic from the ‘B’ port is used.

Note: For STM-1 Tributary Units 25U JU00 750 GVA/GVB and 25U TM00 750 HWE, TU AIS is not propagated across STM-1 tributary links, however, path protection is still provided by using the LP-EXC alarm as the switching trigger (see “VC-12/VC-3 path protection switching” on page 3-11).

TN-1X TN-1X TributariesTributaries

EastWestTN-1X

Drop Insert

Tributaries

TN-1X TN-1X TributariesTributariesEastWest

TN-1X

Drop Insert

Tributaries

West

WestEast

East

Added to makeflattened ring

(a) Drop and insert chain

(b) Drop and insert chain using flattened ring


System overview 2-9

2

Figure 2-5Drop and insert multiplexer ring

STM-4 aggregatesWhen STM-4 Aggregate Units are used, each TN-1X/4 multiplexer is used to provide drop and insert facilities for any one of the four AUGs which make up the STM-4 payload. The remaining three AUGs are routed from aggregate unit A to aggregate unit B, and vice-versa, for onward transmission. In this way, the payload in the ‘East’ and ‘West’ directions (see Figure 2-6) is maintained.

The TN-1X/4 can also be used to provide the grooming function at the ring head. This requires access to one, two, three or four AUGs within the STM-4 aggregate signal and requires a separate TN-1X/4 multiplexer for each AUG to be accessed.

The main application of the Nortel TN-1X/4 multiplexer is in optical rings where it is used to provide access to both private and switched traffic as follows:

• Private Circuit (PC) traffic is routed to other access rings terminating at the same ring head site or alternatively to other remotely sited access rings.

• Switched traffic is routed to the Digital Local Exchange (DLE).

Whilst most of the traffic flow will be from ring node to ring head, some private circuit traffic will be routed between ring nodes and some switched traffic will be routed between remote switches attached to the ring nodes.

Tributaries

East West

TN-1X

TN-1X Tributaries

EastWest

TN-1X

Tributaries

TN-1XTributariesWest

East

East

West


2-10 System overview

Figure 2-6TN-1X/4 multiplexer - STM-1 routing

Figure 2-7 shows a typical deployment of the TN-1X/4 and TN-1X multiplexers in an STM-4 access ring.

STM-4

RX

TX

STM-4STM-1

3

3

STM-1

STM-1

STM-1

STM-4

RX

TX

STM-4

STM-4 OpticalAggregate Unit A

STM-4 OpticalAggregate Unit B

To/fromPayloadManager

East opticaltraffic

West opticaltraffic


System overview 2-11

2

Figure 2-7Typical deployment of the TN-1X/4 in an STM-4 access ring

STM-1 tributariesThe STM-1 Tributary Units provide for the connection of partially filled STM-1 spurs and inter-ring connectivity. Figure 2-8 shows examples of the application of STM-1 tributaries.

Privatecircuits

Privatecircuits

PABX

STM-1spur

STM-1Multiplexer

TN-1X

STM-4access

ring

Ringnode

Ringnode

Ringnode

Ringnode

Privatecircuits

Remote

DLE

STM-4/16

STM-1

STM-4

Private circuitsto other STM-1/STM-16

access rings

Higherlevel

network

Multiple2 Mbit/s or

STM-1

Multiple2 Mbit/s

STM-4 STM-4

STM-4

Note: All paths are bidirectional.

TN-1X/4

TN-1X/4TN-1X/4

TN-1X/4

STM-1

Concentrator Unit

RemoteConcentrator Unit

RemoteConcentrator Unit



Figure 2-8STM-1 tributary configurations

Figure 2-8(a) shows the connection of a partially filled STM-1 spur from a TN-1X (typically a TN-1X/S situated at the customer premises or in street cabinets) to a TN-1X STM-1 ring. In this application, the TN-1X at the customer premises is configured as an unprotected terminal multiplexer and is connected to a STM-1 Tributary Unit at the TN-1X in the STM-1 ring.

Figure 2-8(b) shows the interconnection between a TN-1X STM-1 ring and a TN-1X STM-4 ring. In this application, both TN-1Xs are configured as drop and insert multiplexers with each pair of STM-1 Tributary Units providing interconnections for up to sixty-three TU-12 or three TU-3 channels (or a mix of both up to the VC4 payload capacity).

Figure 2-8(c) shows the interconnection between TN-1X/4s in an STM-4 ring which are dropping/inserting different AU4s, allowing for traffic grooming between AU4s in the ring.

TN-1XTributaries

TN-1X

Tributaries

STM-1

TN-1X/4TN-1X

Tributaries

STM-1

STM-1 Ring

STM-4 RingSTM-1 Ring

(a) STM-1 Spur

(b) Inter-connection of STM Rings

TN-1X/4(AU4-2)

Tributaries

STM-1

STM-4 Ring

(c) Inter-connection of TN-1X/4s using different AU4s in an STM-4 Ring

TN-1X/4(AU4-1)

Tributaries



2

ConnectivityChannel numbering schemes

The Nortel TN-1X uses the ITU-T ‘KLM’ channel numbering system which uses a 3-figure vector (K,L,M) representation to identify the TUG-3, TUG-2 and TU-12 within the VC-4 payload. The KLM scheme also indicates the level of multiplexing, allowing a TUG-3 containing a single TU-3 to be distinguished from a TUG-3 containing seven TUG-2s. This allows, for example, differentiation of a VC-3 (34/45 Mbit/s) signal from a VC-12 (2 Mbit/s) signal:

• ‘1,2,3’ - indicates TUG-3 ‘1’, TUG-2 ‘2’, TU-1 ‘3’ (i.e. a 2 Mbit/s VC-12 signal)

• ‘2,0,0’ - indicates TUG-3 ‘2’ (i.e. a 34/45 Mbit/s VC-3 signal)

Table 2-1 provides cross-references between the K, L, M numbering scheme and the ETSI channel and Nortel numbering schemes used in previous releases.

All user interfaces use the KLM numbering scheme when configuring and displaying connection information. In addition, when using the connection management facility on the Element Controller, the screens also indicate the equivalent ETSI channel numbers.

Port/channel designationsConnections can be made to/from the following tributaries and aggregates. The total tributary capacity of the TN-1X is equivalent to one VC-4, irrespective of the number and capacity of the tributary units.

Note: VC-3 operation is only possible if mixed payload Payload Managers and STM-1 Tributary Units (if applicable) are used.

2 Mbit/s tributaries2 Mbit/s tributary ports are defined by the unit slot number and tributary instance in the form ‘Ss-n’ where:

• ‘s’ is the slot number (‘2’, ‘4’, ‘9’ or ‘11’, i.e. S2, S4, S9 or S11).

• ‘n’ is the tributary port on the indicated unit (‘1’ to ‘16’).

For example:

• ‘S2-2’ is port 2 on the 2 Mbit/s Tributary Unit in slot 2.

• ‘S9-10’ is port 10 on the 2 Mbit/s Tributary Unit in slot 9.

Note: For TN-1X/S, only slot S2 is available for 2 Mbit/s tributary ports.



Table 2-1Channel numbering schemes

TUG-3K

TUG-2L

TU-12M

ETSI(ITU-T)

Nortel TUG-3K

TUG-2L

TU-12M

Nortel ETSI(ITU-T)

111111111111111111111222222222222222222222333333333333333333333

111222333444555666777111222333444555666777111222333444555666777

123123123123123123123123123123123123123123123123123123123123123

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263

122434254672849103152133455163758194061223445264782950113253143556173859204162324456274893051123354153657183960214263

123123123123123123123123123123123123123123123123123123123123123

111222333444555666777111222333444555666777111222333444555666777

111111111111111111111222222222222222222222333333333333333333333

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263

122434254672849103152133455163758194061223445264782950113253143556173859204162324456274893051123354153657183960214263



2

34 Mbit/s tributariesThe 34 Mbit/s Tributary Unit provides access to sixteen constituent 2 Mbit/s signals. For connection purposes, these signals are defined as if they are 2 Mbit/s tributary ports on a 2 Mbit/s Tributary Unit, that is in the form ‘Ss-n’ where:


• ‘n’ is the tributary instance on the indicated unit (‘1’ to ‘16’).

Note: The 34 Mbit/s Tributary Unit is not available on the TN-1X/S.

STM-1 tributariesSTM-1 tributary channels are defined by the unit slot number and the KLM channel number in the form ‘Ss-n-Jj-Kklm’ where:


• ‘n’ is the port number (always ‘1’ for STM-1 tributaries).

• ‘j’ is the AU-4 selection (always ‘1’ for STM-1 tributaries).

• ‘klm’ is the KLM reference

— for VC-12s, ‘k’= ‘1’ to ‘3’, ‘l’ = ‘1’ to ‘7’, ‘m’ = ‘1’ to ‘3’

— for VC-3s, ‘k’ = ‘1’ to ‘3’, ‘l’ = ‘0’, ‘m’ = ‘0’.

For example:

• ‘S4-1-J1-K213’ is TUG-3 ‘2’, TUG-2 ‘1’, TU-1 ‘3’ on STM-1 Tributary Unit in slot 4.

• ‘S11-1-J1-K300’ is TUG-3 ‘3’ (i.e. a VC-3 signal) on STM-1 Tributary Unit in slot 11.

STM-1 aggregatesSTM-1 aggregate channels are defined by the unit slot number and the KLM channel number in the form ‘Ss-n-Jj-Kklm’ where:

• ‘s’ is the slot number (‘6’ or ‘7’, i.e. S6 (Aggregate A) or S7 (Aggregate B)).

• ‘n’ is the port number (always ‘1’ for STM-1 aggregates).

• ‘j’ is the AU-4 selection (always ‘1’ for STM-1 aggregates)



— for VC-3s, ‘k’ = ‘1’ to ‘3’, ‘l’ = ‘0’, ‘m’ = ‘0’.

For example:

• ‘S6-1-J1-K271’ is TUG-3 ‘2’, TUG-2 ‘7’, TU-1 ‘1’ on STM-1 Aggregate Unit in slot 6 (aggregate A).

• ‘S7-1-J1-K100’ is TUG-3 ‘1’ (i.e. a VC-3 signal) on STM-1 Aggregate Unit in slot 7 (aggregate B).



STM-4 aggregatesSTM-4 aggregate channels are defined by the unit slot number and the KLM channel number of the selected dropped AU-4 in the form ‘Ss-n-Jj-Kklm’ where:

• ‘s’ is the slot number (‘6’ or ‘7’, i.e. S6 (Aggregate A) or S7 (Aggregate B)).

• ‘n’ is the port number (always ‘1’ for STM-4 aggregates).

• ‘j’ is the AU-4 selection (‘1’ to ‘4’)



— for VC-3s, ‘k’ = ‘1’ to ‘3’, ‘l’ = ‘0’, ‘m’ = ‘0’.

For example:

• ‘S6-1-J2-K152’ is TUG-3 ‘1’, TUG-2 ‘5’, TU-1 ‘2’ on AU-4 ‘2’ on STM-4 Aggregate Unit in slot 6 (aggregate A).

Connection typesThere are three possible types of connections which are shown in Figure 2-9 and described in subsequent sections.

Figure 2-9TN-1X connection types

2M T

RIB

S

ST

M-1

TR

IB

TN-1X

KEYTU-12

TU-12 PROTECT

VC-3

VC-3 PROTECT

STM-1

STM-1 AGGRSTM-1 AGGR

. . .

Note: It is not possible to concurrently connect all the connections shown above, as the STM-1 bandwidth would be exceeded.



2

Through connectionsA through connection connects a payload channel (VC-12 or VC-3) from one aggregate to the same payload channel on the other aggregate. For example, it is possible to make a through connection between the ‘S6-1-J1-K111’ (aggregate A) and ‘S7-1-J1-K111’ (aggregate B).

Unprotected drop/insert connectionsAn unprotected drop/insert connection connects a VC-12 or VC-3 tributary signal to a payload channel on one of the aggregates. In the event of failure, an alternative routing via the other aggregate is NOT available. For example, it is possible to make an unprotected connection between ‘S2-1’ (tributary 1 on 2 Mbit/s Tributary Unit in slot 2) and ‘S6-1-J1-K333’ (aggregate A).

Protected drop/insert connectionsA protected drop/insert connection connects a VC-12 or VC-3 tributary signal to the same payload channel on both aggregates. In the transmit direction, the tributary signal is transmitted on both aggregates. In the receive direction, the signal is received from both aggregates but only one of the signals is dropped to the tributary. In the event of failure of the signal from the selected aggregate, the signal from the other aggregate is dropped to the tributary. For example, it is possible to make a protected connection between S9-1-J1-K300 (VC-3 signal on STM-1 Tributary Unit in slot 9) and S6-1-J1-K200 (aggregate A) and S7-1-J1-K200 (aggregate B).

Internal traffic connectionsFor internal traffic connections between the traffic cards, the TN-1X uses an internal backplane traffic bus architecture that has a bandwidth of a single STM-1 signal (see Chapter 4 for details). In most circumstances, the TN-1X automatically allocates bandwidth (timeslots) on the internal traffic busses to new connections as required and the internal busses are invisible to the user.

Under certain circumstances, however, the internal bus timeslots may have been used in a way that further connections cannot be made without reallocating existing connections on the internal busses (i.e. the internal busses are fragmented). When this occurs, the user can initiate a reallocation of timeslots on the internal busses, this is known as ‘defragmentation’.

DefragmentationIf an attempt is made to add a new connection when the internal busses have become fragmented, the internal busses may need to be defragmented before the new connection can be made. The defragmentation action can also be user initiated at any time so as to minimise problems when adding future connections.

Note: During the defragmentation action, PPI-Unexp_Signal and PPI-CV_QOSV_15M alarms may be raised as connections are broken and remade.

When the internal busses are defragmented, traffic hits may occur (the user is given a list of possible traffic hits before the defragmentation action is performed).



Note: The physical connections for aggregate and tributary payloads are unchanged by defragmentation, only the internal bus allocation is changed.

Defragmentation of the internal busses can be performed in one of two ways:

• VC-3 optimised. This option optimises the internal bus timeslot allocation for VC-3 connections and minimises the traffic hits associated with future VC-3 connections.

• VC-12 optimised. This option optimises the internal bus timeslot allocation for VC-12 connections and minimises the traffic hits associated with future VC-12 connections. However, whenever possible, TUG-3s are left unallocated, minimising traffic hits associated with future VC-3 connections.

Defragmentation may be necessary under the following conditions:

• When a VC-12 connection is required to a 2 Mbit/s Tributary Unit and the internal operation of the 2 Mbit/s Tributary Unit requires the internal bus timeslots be reassigned.

• When a VC-3 connection is required and an empty TUG-3 (i.e. 21 contiguous timeslots) is not available.

• When a VC-3 connection is required and more than 42 VC-12 connections are already made. The user will have to remove some of the VC-12 connections in order to make enough capacity available, however, the internal bus allocation may have to be reassigned to make an empty TUG-3 available.

Traffic connectionsWhen the Subrack Controller is requested to connect a particular tributary port to a specific aggregate channel (drop/insert connection) or connect between aggregate channels (through connection), a validity check is first made to check if the ports and channels are already in use. The potential endpoints (tributary or aggregate port/channel) for the connection will be in one of the following states:

• Connected. The endpoint is already used in connection and is not available for a new connection.

• Free. The endpoint is not used and is free for a new connection without affecting existing traffic connections.

• Blocked. The endpoint is not used but there is insufficient bandwidth available for it to be used for a new connection. This will occur if:

— a VC-3 connection is required but not enough bandwidth is available on the appropriate Aggregate Unit or an STM-1 Tributary Unit (i.e. the Aggregate Unit or STM-1 Tributary Unit is using the equivalent of more than 42 VC-12s).

— a VC-3 connection is required but an empty TUG-3 is not available on an Aggregate Unit or an STM-1 Tributary Unit.

— a VC-3 connection is required but insufficient bandwidth is available on the internal busses.



2

Under these circumstances, the user will have to delete some connections in order to make the necessary bandwidth available.

• Hit risk. The endpoint is not in use but a defragmentation will be required before making the connection. This will occur if:

— a VC-3 connection is required and, although enough bandwidth is available on the internal busses, the internal busses will need to be defragmented to make an TUG-3 available.

— a VC-12 or VC-3 connection is required and the internal busses will need to be defragmented to reallocate existing connections on a 2 Mbit/s Tributary Unit(s) due to the internal operation of the 2 Mbit/s Tributary Unit.

The default configuration provides sixty-three VC-12 through connections (e.g. Aggregate A K111 to Aggregate B K111, Aggregate A K112 to Aggregate B K112).

As the default setting provides sixty-three VC-12 through connections, to provide a protected terminal multiplexer configuration with two aggregate units it is necessary to make protected tributary connections for all the tributaries. All sixty-three through connections will have to be disconnected before making the tributary connections.

To provide an unprotected terminal multiplexer with a single aggregate unit (i.e. for unprotected point-to-point systems, or end terminals in a drop and insert chain), all sixty-three through connections will have to be disconnected and the unused aggregate port unequipped before making the unprotected connections.

Standby connectionsEach PDH port can be set to traffic auto mode (default) or traffic standby mode via the User Interface.

In the traffic auto mode:

• if a connection exists and there is no signal, a PPI-LOS alarm is raised.

• if no connection exists and a signal is encountered, a PPI-Unexp_Signal alarm is raised.

In the traffic standby mode:

• if a connection exists and a signal is detected, a PPI-Unexp_Signal alarm will be raised but the traffic on the tributary is still carried by the multiplexer.

• if no connection exists, no PPI-LOS or PPI-Unexp_Signal alarms are raised.

The standby mode can be used to set up standby connections. The drop/insert connection is set up in the usual way and then the traffic mode is set to standby. No alarms will be generated until the physical traffic connection is made to the port. Once the physical traffic connection is made, a



PPI-Unexp_Signal will be raised but the traffic signal will be carried by the multiplexer. The PPI-Unexp_Signal alarm can then be removed by setting the port to the traffic auto mode.

User labelsEach connection can be given a user label of up to 15 characters to allow users to assign customer names to connections. The allowable characters are the alpha-numeric characters (A-Z, a-z, 0-9) and underscore (_). The user labels are displayed on all alarm and performance monitoring messages and reports associated with connections.

Engineering Order WireThe TN-1X contains provision for an Engineering Order Wire (EOW) facility which provides a dedicated telephone communication system for maintenance purposes between TN-1Xs in a ring or line configuration. The facility only operates over a single ring or chain and does not support branches or multiple rings/chains. A maximum of 99 nodes are allowed in the ring or chain.

The EOW system uses the E1 or E2 bytes (hardware selectable) in the STM section overhead to provide a 64 kbit/s voice communication channel between TN-1Xs. If the path section is invalid (i.e. out of alignment), the communication path is disconnected.

Note: It is the operators responsibility to ensure the both ends of a path segment are set to use the same EOW byte.

The EOW system requires a single EOW Unit at each TN-1X in the network (even at sites where no EOW access is required). The EOW system uses a standard DTMF telephone which is connected to the Local Craft Access Panel on the TN-1X or the EOW/CATT Connector Panel on the TN-1X/S.

end of chapter


3-1

3
Equipment description 3-
The Nortel TN-1X can be divided functionally into the following three main areas which are described in subsequent chapters:

• Traffic processing (Chapter 4)

• Equipment management (Chapter 5)

• Power and synchronisation (Chapter 6)

The Nortel TN-1X also provides for optional external alarms and Engineering Order Wire (EOW) facilities. A block diagram of the Nortel TN-1X is given in Figure 3-1, a block diagram of the Nortel TN-1X/S is given in Figure 3-2.

EquipmentTN-1X subrack

The upper section of the subrack houses the plug-in units. The lower section of the subrack is the Station Interface Area which houses the Interface Modules and associated cabling, minimising site installation time, and providing easy connector access during maintenance. A moulded cover, mounted on a slide and tilt hinge mechanism, protects the cables during normal operation. The cover also provides a write-on label, beneath a clear protective sheet, for customer information.

The middle section of the subrack contains a fibre routing tray and a Local Craft Access Panel. The fibre routing tray routes the optical fibres from the optical units via adjustable moulded fibre guides to either the left-hand or right-hand side of the subrack. The tray contains hinged moulded covers that protect the fibres in normal use. Fibre guides mounted on the side of the subrack allow the fibres to be routed up or down the rack. The Local Craft Access Panel provides easy access to frequently used facilities.

Details of the subrack are given in “Construction” on page 3-23.

TN-1X/S subrackThe upper section of the subrack houses the plug-in units. The lower section of the subrack is the Station Interface Area which houses the Interface Modules and associated cabling. Additional space should be left below the subrack to enable access to the Service Interface Area for installation and maintenance. Mounted in front of the Interface Modules are a fibre routing tray and the tributary connector panels.


3-2 Equipment description

The fibre routing tray routes the optical fibres from the optical units via adjustable moulded fibre guides to the left-hand side of the subrack. The tray contains hinged moulded covers that protect the fibres in normal use. At the right hand side of the fibre tray, behind the hinged cover, the EOW/CATT Connector Panel provides easy access to frequently used facilities.

The 75 Ω or 120 Ω connector panel enables access to all tributary cabling from the front of the subrack and has two positions. The forward position is used whilst the incoming and outgoing tributary cables are being wired to the subrack. The panel is then moved to the rearward position. The special extended screws are threaded at two points to allow the connector panel to be fixed in either position.

Details of the subrack are given in “Construction” on page 3-23.

Figure 3-1Nortel TN-1X - block diagram

34 Mbit/sTributaryUnit

2048 kbit/sInterfaces (G.703)

STM-1TributaryUnit Payload

Manager(Main)

Traffic Processing

STM-NPorts

PowerUnit

StationBattery

InternalDerivedSupplies

SubrackController

Monitoring/Control

LocalTerminal

Rack Alarm Bus

SynchronisationInput/Output

Power Equipment Management

AggregateUnit (A)



(Standby)

AggregateUnit (B)

NetworkManagement


ExternalAlarms

E1/E2OH ByteAccess

EOWHandset


EOWUnit


Equipment description 3-3

3

Figure 3-2Nortel TN-1X/S - block diagram

Subrack layoutsThe layout of the subrack is shown in Figure 3-3 (TN-1X) and Figure 3-4 (TN-1X/S). The unit subrack position numbers are those used by the software and are indicated above the plug-in units, the subrack slot position is the backplane connector designation. The prefix ‘S’ is used to indicate a plug-in unit slot position, the prefix ‘T’ is used to indicate the Interface Module slot position. These prefixes do not appear on the software screens or the equipment.

VariantsEach equipped subrack variant of the Nortel TN-1X and Nortel TN-1X/S caters for a specific complement of units (e.g. type of aggregate unit, number of tributary units, types of interface module).

Each of the individual units also has an unique 13-digit code. Each type of unit may also have a number of variants in order to cater for customer requirements (e.g. front panel details). The codes of the available units are detailed in Chapter 9, “Equipment codes”.


STM-1TributaryUnit

STM-1TributaryUnit Payload

Manager(Main)

Traffic Processing

STM-NPorts

PowerUnit

StationBattery

InternalDerivedSupplies

SubrackController

Monitoring/Control

LocalTerminal

Power Equipment Management

AggregateUnit (A)


(Standby)

AggregateUnit (B)


ExternalAlarms

EOWUnit

E1/E2OH ByteAccess

EOWHandset


3-4 Equipm

ent description

323-1

Fig

ure 3-3

No

rtel TN

-1X - su

brack layo

ut

n Tributary Unit/Spare*

ger A

it A

it B

ger B

roller

S1

S2

S3

S4

S5

S6

S7

S8

S9

S10

S11

S12

S13

S14

16

1116

2126

3442

4752

5762

7180

SubrackS

lotP

osition

Unit

Subrack

Position

061-100 Release 7 S

tandard (Revision 1)

Tributary Unit

EOW Unit

N+1 Protectio

Payload Mana

Aggregate Un

Aggregate Un

Payload Mana

Spare**

Power Unit

Tributary Unit

Tributary Unit

Tributary Unit

Subrack Cont

Power Unit

Fibre S

torage Tray

Local Craft A

ccess Panel

Low Speed Ports 1 to 8 (S2)

Flexible Access Module








Star Card

Not Used

Not Used

Not Used

High Speed Aggregate Ports

High Speed Aggregate Ports

Station Service Module

Station

InterfaceA

rea

110

1525

3035

4045

5055

6570

80

InterfaceM

oduleS

ubrackP

osition

SubrackS

lotP

osition

T1

T2

T3

T4

T5

T6

T7

T8

T9

T10

T11

T12

T13

T14

T15

T16

* not spare when a 2” S

TM

-1 Tributary Unit fitted in position S

2.** not spare w

hen a 2” ST

M-1 Tributary U

nit fitted in position S9.


3

Figure 3-4Nortel TN-1X/S - subrack layout

Plug-in unitsThe Nortel TN-1X and TN-X/S subracks provide dedicated plug-in unit positions for the following plug-in units:

• Power Unit, (1 or 2 off) which fit into subrack positions S12 and S13.

The Power Units provide the regulated d.c. outputs for the other units in the subrack. When two Power Units are fitted, they operate as a load sharing pair. If one of the units fails, the other unit can supply the total power requirement.

• Subrack Controller, (1 off) which fits into subrack position S14.

The Subrack Controller performs general control and monitoring functions.

• Payload Manager, (1 or 2 off) which fit into subrack positions S5 and S8.

The Payload Manager provides a drop and insert facility, and a reordering facility at the TU level of the SDH. TU-3 operation is only possible when using the mixed payload Payload Manager (NTKD10AA). When two units are fitted they operate in a main/standby configuration to provide protection against a Payload Manager or backplane failure. In normal operation, both units are active but the outputs of the standby unit are disabled.

Trib

utar

y U

nit

EO

W

Spa

re*

ST

M-1

Trib

utar

y U

nit

Pay

load

Man

ager

Agg

rega

te U

nit

Agg

rega

te U

nit

Pay

load

Man

ager

ST

M-1

Trib

utar

y U

nit

Spa

re*

ST

M-1

Trib

utar

y U

nit

Pow

er U

nit

Pow

er U

nit

Sub

rack

Con

trol

ler

Low Speed Ports 1 to 8

Low Speed Ports 9 to 16

Power & LCAP

Flexible Termination/Ext Alm

SubrackSlot

Position

S1 S2 S3 S4 S5 S7S6 S8 S10S9 S11 S12 S14S13

1 6 11 16 21 3426 42 5247 57 62 8071

UnitSubrackPosition

Interface Module Subrack Position

M1A

M1B

* not spare when a 2” STM-1 Tributary Unit fitted in position S2.** not spare when a 2” STM-1 Tributary Unit fitted in position S9.



• EOW Unit, (1 off) which fits into subrack position S1. Two versions of the EOW Unit are available as follows:

— The EOW Unit (25U SV00 750 GVX), also known as ICC1, provides internal telephone communication between TN-1Xs in a network. The unit interfaces with a standard DTMF telephone and provides the analogue/PCM coding/decoding using A-law companding. The 64 kbit/s PCM data is transferred via the backplane overhead bus to the aggregate units for transmission via the E1 or E2 bytes in the section overhead.

— The EOW Unit (NTFT13AA), also known as ICC2, provides all the EOW facilities provided by the 25U SV00 750 GVX variant. The unit also is used to control N+1 protection of 2 Mbit/s Tributary Units (see ‘N+1 2 Mbit/s tributary protection’ on page 3-15).

The Nortel TN-1X and TN-X/S subracks provide six general purpose tributary unit positions (maximum of five used on TN-1X, maximum of four used on TN-1X/S).

The following tributary plug-in units are available:

• 2 Mbit/s Tributary Unit, 75 Ω or 120 Ω

Each 2 Mbit/s Tributary Unit provides sixteen 2048 kbit/s interfaces, conforming to ITU-T recommendation G.703. For each tributary, the unit performs the mapping of the tributary into a VC-12 of the SDH and generates the TU pointer, thus producing a TU-12. The unit performs the corresponding pointer processing and demapping in the opposite direction.

• STM-1 Tributary Unit, optical or electrical

Each STM-1 Tributary Unit provides an STM-1 tributary port with access to a maximum of sixty-three VC-12 channels or three VC-3 channels (or a combination of the two). The unit performs the STM-1 section overhead processing, the TU reordering, and the electrical/optical conversions (STM-1 Optical Tributary Unit) or the CMI coding/decoding (STM-1 Electrical Tributary Unit).

Note 1: The TN-1X/S does not support STM-1 Electrical Tributary Units.

Note 2: VC-3 operation is only possible using the mixed payload STM-1 Tributary Units (NTKD11AA and NTKD12AA).

• 34 Mbit/s Tributary Unit, 75 Ω

Each 34 Mbit/s Tributary Unit provides a 34368 kbit/s interface, conforming to ITU-T recommendation G.703. The unit performs demultiplexing of the 34368 kbit/s signal according to ITU-T recommendations G.742 and G.751 into sixteen 2048 kbit/s plesiochronous channels. For each channel, the unit performs the mapping of the channel into a VC-12 of the SDH and generates the TU pointer, thus producing a TU-12. The unit performs the corresponding pointer processing, demapping, and multiplexing in the opposite direction.

Note: The TN-1X/S does not support 34 Mbit/s Tributary Units.



3

The Nortel TN-1X and TN-X/S subracks provide two general purpose aggregate unit positions for the following plug-in units:

• STM-1 Aggregate Unit, optical or electrical

— The STM-1 Aggregate Unit performs the STM-1 section overhead processing and the electrical/optical conversions (STM-1 Optical Aggregate Unit) or the CMI line coding/decoding (STM-1 Electrical Aggregate Unit).

Note: The TN-1X/S does not support STM-1 Electrical Aggregate Units.

• STM-4 Optical Aggregate Unit

— The STM-4 Optical Aggregate Unit performs the STM-4 electrical/optical conversions, the STM-4 section overhead processing, and the dropping/insertion of one of the AUGs within the STM-4 signal.

The TN-1X and TN-1X/S subrack are designed so that the tributary and aggregate positions can be equipped in later versions of the multiplexer with other tributary and aggregate units to provide a wider range of features.

TN-1X subrack - tributary and aggregate optionsFor present Nortel TN-1X subracks, the tributary and aggregate positions can be occupied by the following plug-in units.

• tributaries

— 2 Mbit/s Tributary Unit, 75 Ω or 120 Ω (up to 4 off) orSTM-1 Optical or Electrical Tributary Unit (up to 4 off)or34 Mbit/s Tributary Unit (up to 4 off)

The units fit into subrack positions S2, S4, S9, and S11. The 2” variant of the STM-1 Tributary Unit occupies two slots and can only be fitted in positions S2 and S9 (i.e. unit in position S2 occupies slots S2 and S3, unit in position S9 occupies slots S9 and S10).

If N+1 protection is required, a 2 Mbit/s Tributary Unit is fitted in subrack position S3 (see ‘N+1 2 Mbit/s tributary protection’ on page 3-15 for more details of N+1 requirements).

• aggregates

— STM-1 Optical or Electrical Aggregate Unit (up to 2 off)orSTM-4 Optical Aggregate Unit, 1310 nm or 1550 nm (up to 2 off)orone STM-1 Aggregate Unit and one STM-4 Aggregate Unit

These units fit into subrack positions S6 and S7.



TN-1X/S subrack - tributary and aggregate optionsFor present Nortel TN-1X/S subracks, the tributary and aggregate positions can be occupied by the following plug-in units.

• tributaries

— 2 Mbit/s Tributary Unit, 75 Ω or 120 Ω (1 off)orSTM-1 Optical Tributary Unit (up to 4 off).

The 2 Mbit/s Tributary Units fit into subrack positions S2 only. The STM-1 Tributary Units fit into subrack positions S2, S4, S9, and S11. The 2” variant of the STM-1 Tributary Unit occupies two slots and can only be fitted in positions S2 and S9 (i.e. unit in position S2 occupies slots S2 and S3, unit in position S9 occupies slots S9 and S10).

• aggregates

— STM-1 Optical Aggregate Unit (up to 2 off)orSTM-4 Optical Aggregate Unit, 1310 nm only (up to 2 off)orone STM-1 Aggregate Unit and one STM-4 Aggregate Unit (1310 nm only)

These units fit into subrack positions S6 and S7.

Interface modulesThe Interface Modules provide the external electrical connections. There are two types of Interface Modules:

• Traffic Interface Modules (TIMs) which provide the traffic connectors.

• Service Interface Modules (SIMs) which provide the general rack connectors.

TN-1XThe following SIMs and TIMs are available:

• 75 Ω Traffic Access Module. The 75 Ω Traffic Access Module provides connections for eight 2 Mbit/s 75 Ω tributary ports. Two modules are required for the full 16 channels of a 2 Mbit/s Tributary Unit.

• 75 Ω Traffic Access Module N+1 Protection. The 75 Ω Traffic Access Module N+1 Protection provides connections for eight 2 Mbit/s 75 Ω tributary ports. The module also contains the relays used to switch traffic when N+1 protection is employed. Two modules are required for the full 16 channels of a 2 Mbit/s Tributary Unit.

• 120 Ω Traffic Access Module. The 120 Ω Traffic Access Module provides connections for eight 2 Mbit/s 120 Ω tributary ports. Two modules are required for the full 16 channels of a 2 Mbit/s Tributary Unit.

• 120 Ω Traffic Access Module N+1 Protection. The 120 Ω Traffic Access Module N+1 Protection provides connections for eight 2 Mbit/s 120 Ω tributary ports. The module also contains the relays used to switch traffic when N+1 protection is employed. Two modules are required for the full 16 channels of a 2 Mbit/s Tributary Unit.



3

• High Speed Traffic Access Module. The High Speed Traffic Access Module provides connections for a 34 Mbit/s 75 Ω tributary port.

• High Speed Aggregate Module. The High Speed Aggregate Module provides connections for a STM-1 electrical aggregate port.

• High Speed Tributary Module. The High Speed Tributary Module provides connections for a STM-1 electrical tributary port.

• Station Service Module. The Station Service Module provides connections for the rack alarm bus, the management Q3 port (LAN), and power.

• 75 Ω Star Card. The 75 Ω Star Card provides connections for the external synchronisation timing ports.

• Flexible Access Module. The Flexible Access Module provides the connections to the LCAP. A variant is provided that also provides connections to the LCAP and connections for up to 5 external alarms.

TN-1X/SThe following SIMs and TIMs are available:

• 75 Ω Traffic Access Module. The 75 Ω Traffic Access Module provides connections for eight 2 Mbit/s 75 Ω tributary ports to the 75 Ω Connector Panel. Two modules are required for the full 16 channels of a 2 Mbit/s Tributary Unit.

• 120 Ω Traffic Access Module. The 120 Ω Traffic Access Module provides connections for eight 2 Mbit/s 120 Ω tributary ports to 120 Ω Connector Panel. Two modules are required for the full 16 channels of a 2 Mbit/s Tributary Unit.

• Flexible Termination Module. The Flexible Termination Module fills the empty position in the SIA below the Power & LCAP (Local Craft Access Panel) module and maintains EMC screening.

• Power & LCAP Service Interface Module. The Power & LCAP Service Interface Module provides the connector for power and through connections to the EOW/CATT connector panel.

• External Alarm Interface Module.The External Alarm Interface Module is fitted instead of Flexible Termination Module if external alarm facilities are required and provides the connections for up to 5 external alarms.

TIM allocation - TN-1XThe allocation of the TIMs to the 2 Mbit/s Tributary Units in the TN-1X subrack is as follows:

TIM in position T2 provides 2048 kbit/s ports 1 to 8 for position S2TIM in position T3 provides 2048 kbit/s ports 9 to 16 for position S2TIM in position T5 provides 2048 kbit/s ports 1 to 8 for position S4TIM in position T6 provides 2048 kbit/s ports 9 to 16 for position S4TIM in position T10 provides 2048 kbit/s ports 1 to 8 for position S9TIM in position T11 provides 2048 kbit/s ports 9 to 16 for position S9TIM in position T13 provides 2048 kbit/s ports 1 to 8 for position S11TIM in position T14 provides 2048 kbit/s ports 9 to 16 for position S11.



The allocation of the TIMs to the 34 Mbit/s Tributary Units in the TN-1X subrack is as follows:

TIM in position T3 provides 34368 kbit/s port for position S2TIM in position T6 provides 34368 kbit/s port for position S4TIM in position T11 provides 34368 kbit/s port for position S9TIM in position T14 provides 34368 kbit/s port for position S11.

The allocation of the TIMs to the STM-1 Electrical Tributary Units is as follows:

TIM in position T3 provides STM-1 port for position S2TIM in position T6 provides STM-1 port for position S4TIM in position T11 provides STM-1 port for position S9TIM in position T14 provides STM-1 port for position S11.

The allocation of the TIMs to the STM-1 Electrical Aggregate Units is as follows:

TIM in position T7 provides STM-1 port for position S6TIM in position T9 provides STM-1 port for position S7.

TIM allocation - TN-1X/SThe allocation of the TIMs to the 2 Mbit/s Tributary Units in the TN-1X/S subrack is as follows:

TIM in position M1A provides 2048 kbit/s ports 1 to 8 for position S2TIM in position M1B provides 2048 kbit/s ports 9 to 16 for position S2.

Connector panelsThe connector panels are located at the front of the Station Interface Area of the TN-1X/S.

• 75 Ω Connector Panel. The panel provides SMB connections for sixteen 2 Mbit/s 75 Ω tributary ports.

• 120 Ω Connector Panel. The panel provides four 25-way D-type connections for sixteen 2 Mbit/s 120 Ω tributary ports.

• EOW/CATT Connector Panel. The panel provides access to the subrack alarm facilities (alarm LEDs, receiving attention push-button switch) and the local terminal and EOW connectors.

Details of the Connector Panels are given in a Chapter 8 ‘External interfaces’.

Local Craft Access PanelThe Local Craft Access Panel (LCAP) is mounted centrally at the front of the TN-1X subrack and provides the interfaces commonly used by installation and maintenance engineers, together with the subrack alarm facilities. The right-hand side of the panel contains the subrack alarm facilities (alarm LEDs, receiving attention push-button switch), and an ESD bonding point. A hinged cover on the face plate provides access to the commonly used connectors. The LCAP interfaces with the Subrack Controller via the SIM in position T1. Details of the LCAP are given in a Chapter 8, “External interfaces”.



3

VC-12/VC-3 path protection switchingFor the Nortel TN-1X, the Subrack Controller can provide autonomous Path Protection Switching (PPS) at the VC-12 and VC-3 levels. Protection of the VC-12s and VC-3s is performed by transmitting the VCs from both aggregate ports (thus transmitting the VCs both ways round a ring or on both paths of a duplicated point-to-point system) and performing autonomous protection switching between the received VCs at the terminating multiplexer.

Protected VCs occupy the same logical channel at both aggregate ports. Unprotected VCs only occupy a logical channel at one aggregate port, allowing the same logical channel at the other aggregate unit to be used for another unprotected VC.

If an optical fault (e.g. fibre break) occurs, a laser shutdown is initiated (refer to ‘Automatic laser shutdown’ on page 3-21) which causes traffic in both directions of the ring section to be shut down. This results in a dual ended path switch that sustains traffic during an optical fault in one section of the ring.

Modes of operationPath protection switching can be in one of two modes which are selectable via the user interface.

• Automatic In the automatic mode (PPS on), a path protection switch will occur if any of the following alarms exist on the Payload Manager, 2 Mbit/s Tributary Unit or 34 Mbit/s Tributary Unit:

Note 1: The HP alarms cause a protection switch on all the protected VC-12 and VC-3 paths, the LP alarms cause a protection switch on the specific VC-12 or VC-3 path against which the specific alarm was raised.

Note 2: A protection switch will also occur on all protected VC-12 and VC-3 paths as an indirect consequence a RS-LOS, RS-LOF, MS-AIS, MS-EXC and HP-TIM alarms raised on an Aggregate Unit (due to AU-AIS being injected towards the Payload Manager).

Path protection switching is controlled by the user interface and is enabled/disabled for each path separately.

Automatic path protection switching is disabled for 2 minutes after changing the on-line configuration. If a condition which should trigger protection switching occurs during the two minutes, switching will be delayed until the end of the 2 minute period.

PAYLOAD MANAGER 2/34 Mbit/s TRIBUTARY UNIT

High-order Path (HP)

INT- AU-AISINT-AU-LOPHP-LOM

Low-order Path (LP)

TU-AISTU-LOP

LP-EXC(not applicable to VC-3s)



• Manual In the manual mode (PPS off), a path protection switch can be initiated on each path individually via the user interface.

Persistence checksFailure persistence checkTo allow for higher-level protection to occur on other high level systems (e.g. where a protected VC-12 path is through a higher level STM-16 ring) before initiating a path protection switch, a failure persistence check is performed prior to switching. This check period also protects against short glitches causing undesired protection switches.

Restoration persistence checkTo prevent the a protection switch to a faulty path and to prevent excessive oscillations between paths due to LP-EXC alarms being raised on both paths, a restoration persistence check is performed.

A protection switch to the standby path will not occur if the standby path has any of the path failure conditions in the restoration persistence check period (the preceding 30 seconds).

The check on the standby path cannot detect LP-EXC alarm as the standby path is not dropped to the 2 Mbit/s Tributary or 34 Mbit/s Tributary Unit (where the LP-EXC alarm is detected). A protection switch will not occur until after the 30 seconds restoration persistence check period. However, a switch will occur if a LP-EXC alarm is present on both paths after the restoration check period. A switch will then occur every 30 seconds until LP-EXC alarm is cleared from at least one path.

STM-1 tributariesAs described in “Modes of operation” on page 3-11, TU-AIS is used as the main mechanism to trigger automatic path protection switching. When using STM-1 Tributary Unit variants (25U TM00 750 HWG, 25U TM00 750 JBK, NTKD11AA and NTKD12AA), TU-AIS is propagated between aggregate and STM-1 tributary paths, allowing for full subnetwork connection protection.

When using STM-1 Tributary Units 25U JU00 750 GVA/GVB and 25U TM00 750 HWE, TU-AIS is not propagated on the STM-1 tributary links. Path protection on a network containing these STM-1 Tributary Units is provided by using the LP-EXC alarm as the trigger mechanism. This is possible as the BIP-2 bits (part of the V5 path overhead byte) are always set to one during TU-AIS and thus always generate an LP-EXC alarm under TU-AIS conditions.

Note 1: If a network failure leads to both the main and standby paths of a protected channel receiving LP-EXC alarms, protection switching between the main and standby paths will occur every 30 seconds (see “Restoration persistence check” on page 3-12).



3

Note 2: For interoperation with other equipment that does not support LP-EXC triggered path protection, path protection switching is not supported for traffic that traverses a TN-1X STM-1 tributary using STM-1 Tributary Units 25U JU00 750 GVA/GVB and 25U TM00 750 HWE.

Note 3: When using a ‘protected’ STM-1 link, if a ‘HP-TIM’ alarm is raised and AIS is generated as a consequent action, the switch to the other path takes up to 20 seconds. The standby path must be error free for 30 seconds before a switch occurs.

N+1 2 Mbit/s tributary protection N+1 tributary protection allows traffic on any of the 2 Mbit/s Tributary Units to be switched to a protection 2 Mbit/s Tributary Unit in the low-speed tributary protection slot (subrack slot S3). For N+1 protection to be used, the following units/modules must be fitted:

• 2 Mbit/s Tributary Units in the normal (S2, S4, S9, and S11)and protection (S3) slots must be of the same impedance type (75 Ω or 120 Ω).

• the protection 2 Mbit/s Tributary Unit in slot S3 must be one of the latest units (i.e. 25U JU00 750 HVT, 75 Ω, or 25U JU00 750 HVQ, 120 Ω).

• N+1 Protection 2 Mbit/s Traffic Access Modules (TAMs) must be fitted to the subrack. Each 2 Mbit/s Tributary Unit, except the protection 2 Mbit/s Unit, requires two N+1 Protection TAMs.

• the EOW Unit (ICC2) (NTKD13AA) must be equipped.

Note 1: N+1 protection is not supported in the TN-1X/S.

Note 2: Once N+1 tributary protection is enabled, the above units cannot be logically unequipped.

Note 3: N+1 tributary protection can be enabled if the logical equipping is correct even if the physical equipment to support N+1 protection is not present. Ensure that no relevant NE-Card_Out alarms are present, in particular the EOW Unit (ICC2).

Note 4: Early versions (PCS1 and 2) of Payload Manager 25U PJ00 750 GXF will allow N+1 protection to be enabled but do not support it.

In normal operation, the TAMs connect the tributary signals to its assigned 2 Mbit/s Tributary Unit. When a switching condition is raised, the TAMs connect the tributary signals associated with the faulty 2 Mbit/s Tributary Unit to the protection 2 Mbit/s Tributary Unit (all the tributary signals associated with faulty 2 Mbit/s Tributary Unit are switched together).

CAUTIONN+1 2 Mbit/s tributary switchingIf N+1 tributary protection is enabled, do not remove an active 2 Mbit/s Tributary Unit. Perform a manual N+1 protection switch to the protection 2 Mbit/s Tributary Unit before removing an active 2 Mbit/s Tributary Unit.



Modes of operationN+1 protection switching can be in one of the following three modes which are selectable via the user interface.

DisabledWhen N+1 tributary protection is disabled, no protection of the 2 Mbit/s Tributary Unit is provided, even though the necessary units may be equipped.

AutomaticIn the automatic mode, N+1 protection switching is controlled by the multiplexer. An automatic N+1 protection switch will occur if any of the following alarm conditions exist on a 2 Mbit/s Tributary Unit in slot S2, S4, S9 or S11:

NE-Card_OutNE-Card_FailNE-Card_Fault

Once an automatic switch has occurred, no further automatic switches are possible as the protection 2 Mbit/s Tributary Unit is being used to carry traffic. If an automatic switch has occurred, the system does not automatically revert to the original 2 Mbit/s Tributary Unit if the original cause of the switch clears. Reversion to the original 2 Mbit/s Tributary Unit must be performed manually.

ManualIn the manual mode, the protection switch is initiated by the user via the user interface.

Switching prerequisitesBefore a manual or automatic N+1 protection switch can be performed, the following prerequisites must be met:

• The EOW Unit (ICC2), the active Payload Manager and the protection 2 Mbit/s Tributary Unit (slot S3) do not have any NE_Card_Fail, NE_Card_Out, or NE-Card_Fault alarms present.

• The faulty 2 Mbit/s Tributary Unit must have traffic connections made.

• A N+1 protection switch has not already been made, i.e. the protection 2 Mbit/s Tributary Unit (slot S3) does not have traffic connections.

Note: Once a N+1 protection switch has occurred, no further traffic connections can be made to the protection 2 Mbit/s Tributary Unit until the manual reversion is performed.

CAUTIONRebooting a multiplexerPerforming a cold reboot of a multiplexer with N+1 protection enabled and actively protecting a slot, will cause loss of traffic for up to 8 minutes.



3

N+1 tributary switching alarmsThere are a number of alarms associated with N+1 tributary protection switching as follows:

• NE-np1_switch_Alarm. This alarm indicates that a successful manual or automatic switch to the protection 2 Mbit/s Tributary Unit has occurred and the other 2 Mbit/s Tributary Units are no longer protected. The alarm will be cleared when a manual reversion to the original 2 Mbit/s Tributary Unit is performed.

• NE-Card_Out (for TAM slot). This alarm indicates that an N+1 Protection 2 Mbit/s TAM has been removed from the subrack.

• NE-Wrong_Card (for TAM slot). Indicates that a wrong TAM has fitted or the N+1 Protection TAM has failed.

Note 1: The NE-Card_Out and NE-Wrong_Card alarms for TAM slots are only reported if the N+1 tributary protection is enabled.

Note 2: Once the switching action is complete, monitoring of all alarms (except NE-Card_Out and NE-Card_Fail) on the protection 2 Mbit/s Tributary Unit are ignored for 30 seconds to allow spurious alarms to settle.

Payload Manager switchingThe Nortel TN-1X can be fitted with duplicated Payload Managers.

The Payload Managers operate in a main/standby mode with only the traffic outputs of one Payload Manager active at any one time. If the Subrack Controller detects a fault on the main Payload Manager, it instructs the standby Payload Manager to become active (if no faults are present on the standby Payload Manager). The Subrack Controller also instructs the relevant tributary and aggregate units to receive/transmit via the standby Payload Manager. Payload Manager (B) is the default main unit.

CAUTIONPayload Manager switchingDo not remove the active Payload Manager.

A Payload Manager switch will cause temporary loss of traffic. Payload Manager switching should not be performed unless absolutely operationally necessary. Switching between Payload Managers should preferably only be performed during periods of low traffic density.

Payload Manager switches should not be done more often than every 6 minutes on a single NE.



Modes of operationPayload Manager switching can be in one of two modes selectable via the user interface.

• Automatic In the automatic mode, Payload Manager switching is controlled by the Subrack Controller and will occur if any of the following alarm conditions exist on the active Payload Manager:

NE-Card_OutNE-Card_FailNE-Card_FaultINT-NE-Comms_FailINT-SYNC-Oscillator_FailHP-LOM

Note: Automatic Payload Manager switching cannot be enabled unless both Payload Managers are of the same type. This prevents incorrect operation when VC3 traffic is being carried.

• Manual In the manual mode, the protection switch is initiated by the user via the user interface.

Switching prerequisitesBefore a manual or automatic Payload Manager switch can be performed, the following prerequisites must be met:

• the standby Payload Manager is equipped and does not have any of the Payload Manager switching conditions (see above).

• if the Payload Manager switching is automatic, the standby Payload Manager must be the same variant as the active Payload Manager.

• if the Payload Manager switching is manual, no VC-3 connections must be present if switching from a mixed payload Payload Manager to a non-mixed payload Payload Manager.

LoopbackVarious loopback facilities are provided for maintenance and test purposes. For the Nortel TN-1X, the following loopbacks (see Figure 3-5) are provided.

The loopbacks can be set via the user interface.

CAUTIONTraffic disruptionLoopback operation may disrupt traffic, and on occasions the comms/management network may be severely disrupted.



3

Figure 3-5Position of loopbacks

2 Mbit/s Tributary UnitRemote When enabled, tributary input data (after the line interface but prior to HDB3 decoding) is routed to the tributary output (after the HDB3 coding but prior to the line interface). Routing is performed on the Quad 2 Mbit/s ASIC. The tributary input data is still processed by the rest of the unit unless the ‘Local’ loopback is enabled.

Note: Selecting the ‘Remote’ loopback when the selected tributary has no input will cause a ‘PPI-TF’ alarm to be raised.

Local When enabled, tributary output data (after the HDB3 coding but prior to the line interface) is routed to the tributary input (after the line interface but prior to HDB3 decoding). Routing is performed on the Quad 2 Mbit/s ASIC. The tributary output data is still applied to the line interface and output from the unit unless the ‘Remote’ loopback is enabled.

Note 1: For each tributary, only the ‘Remote’ or the ‘Local’ loopbacks can operate at a given time. If both loopbacks are selected for a given tributary, the ‘Local’ loopback will not operate.

TxRx

Aggr, Tx Aggr, Rx

SIRPIT

STM-1Processor

SIRPIT

SIRPIT

SIRPIT

SIRPIT

2M ASIC

2048 kbit/s Signals

2 Mbit/s Ports

STM-1 Signal

STM-1TributaryUnit

PayloadManager

2 Mbit/sTributary Unit

SIRPIT

SIRPIT

STM-1 Signal

STM-1 Aggregate Unit

SIRPIT

2M ASIC

34368 kbit/s Signals

34 Mbit/s Port

Mux/Demux

34 Mbit/sTributary Unit

Key:Remote

Local



Note 2: Do not apply a ‘Local’ loopback for a tributary selected as the active synchronisation source, otherwise the multiplexer will lose synchronisation.

Note 3: Loopbacks on 2 Mbit/s Tributary Unit variants 25U JU00 750 HVQ/HVT work correctly except for the alarms that are reported when the loopbacks are applied. For example, if a 2 Mbit/s tributary connection is made and there is no traffic input, a ‘PPI-LOS’ alarm is reported as expected. When a ‘Local’ loopback is applied to that tributary port, the ‘PPI-LOS’ alarm should clear. However, when using these variants of the 2 Mbit/s Tributary Unit’ the alarm does not clear but traffic is restored. Conversely, whenever there is no connection associated with a tributary port and a ‘Local’ loopback is applied to that port, ‘PPI-Unexp_Signal’ and ‘PPI-AIS’ would be expected to be reported. However, when using these variants of the 2 Mbit/s Tributary Unit’, the alarms are not reported.

STM-1 Aggregate Unit/STM-1 Tributary UnitRemote When enabled, the serial input data is routed to the serial output on the external output SIRPIT, the normal serial output from the parallel/serial conversion being disabled. This loopbacks the data from the receiver to the transmitter. The serial input data from the receiver is still converted to parallel data and applied to the STM-1 Processor ASIC.

Local When enabled, the parallel output data is routed to the parallel input data on the external output SIRPIT, the normal parallel input from the receiver being disabled. This loopbacks the parallel data to the STM-1 Processor. The parallel output data from the STM-1 Processor is still converted to serial data and applied to the transmitter.

Note: For each STM-1 Aggregate Unit or STM-1 Tributary Unit, both the ‘Remote’ and ‘Local’ loopbacks should not be applied simultaneously.

34 Mbit/s Tributary UnitRemote When enabled, the 34 Mbit/s tributary input data (prior to demultiplexing) is routed to the 34 Mbit/s tributary output. The tributary input data is still processed by the rest of the unit unless the ‘Local’ loopback is enabled.

Note 1: The 34 Mbit/s Loop to Line loopback is enabled by selecting any of the 2 Mbit/s loop to line loopbacks for the 34 Mbit/s Tributary Unit from the user interface.

Note 2: Selecting ‘Local’ will affect all sixteen 2 Mbit/s channels.

Local When enabled, 2 Mbit/s channel data (prior to multiplexing) is routed back towards the Payload Manager. Routing is performed on the Quad 2 Mbit/s ASIC. The 2 Mbit/s channel data is still applied to the multiplexer and output from the unit unless the ‘Remote’ loopback is enabled.



3

Single fibre workingThe Nortel TN-1X is capable of operating in a single fibre mode whereby a single optical fibre is used to carry bi-directional optical signals between adjacent multiplexers. The conversion between two fibre working and single fibre working is performed externally to the multiplexer by a 2-1 optical converter box (see Figure 3-6).

Figure 3-6Nortel TN-1X - single fibre operation

If a break occurs in the single fibre, there is a possibility of the transmitted traffic being echoed by the 2-1 optical converter box to the receive port on the same multiplexer. This signal must be recognised as faulty and AIS transmitted downstream. To recognise the echoed signal, the HP path trace facility should be used with the transmit and receive path trace settings set to different values and the consequent actions enabled.

By using the path trace facility with the consequent actions enabled, a HP-TIM alarm will be raised and AIS transmitted downstream if a fibre break occurs.

Note 1: If HP-RDI is enabled as a consequent action of a HP-TIM alarm, the transmitted signal will have the HP-RDI set. This will be received in the echoed signal causing a HP-RDI alarm to be raised on the same multiplexer that generated it.

Note 2: If consequent actions are enabled for the HP-TIM alarm, detection of a HP-TIM alarm on an STM-1 Aggregate Unit or an STM-1 Tributray Unit will assign that card as a failed synchronisation source if it was in the synchronisation hierarchy. The same also applies to the STM-4 Aggregate Unit but a Qecc-Comms_Fail alarm must also be dtected against an Aggregate Unit before a synchronisation source switch will occur.

In the event of a broken fibre where the echo is sufficient to constitute a valid signal, the multiplexer does not behave in the normal manner to a Loss of Signal event. Instead a transient RS-LOF alarm will be raised whilst the multiplexer is achieving frame alignment to the echoed signal.

The RS-LOS alarm is used as a trigger for automatic laser shutdown (ALS). In the event of a broken fibre, if the echo is sufficient to constitute a valid signal, the RS-LOS will not be raised, therefore ALS is not supported when operating in a single fibre mode.

SingleOpticalFibre

Nortel TN-1X

Tx

Rx 2-1

Con

vert

er

2-1

Con

vert

er

Nortel TN-1X

Tx

Rx



Automatic laser shutdownNote: Automatic laser shutdown is not supported if the multiplexer is operating in a single fibre mode.

The STM-1 Optical Aggregate Units, STM-1 Optical Tributary Units and the STM-4 Optical Aggregate Units contain an Automatic Laser Shutdown (ALS) circuit which shuts down the laser if an OS-Optical_Power_High or an RS-LOS alarm occurs. This prevents excessive optical power being radiated from a broken fibre or an unterminated optical connector.

The laser is shut down if the RS-LOS alarm is present for greater than approximately 525 ms or immediately by an OS-Optical_Power_High alarm. If the RS-LOS alarm clears, the laser is switched back on immediately. If the shutdown is initiated by an OS-Optical_Power_High alarm, the laser can not be restarted until the unit is reset (e.g. removed and replaced in the subrack).

On power-up of the unit, the laser is held on for 2 seconds irrespective of the alarm conditions. The automatic restart periodically forces the laser on for 2 seconds until the laser restart is successful. The period between laser restarts is dependent on the variant as follows:

64 seconds: STM-1 Aggregate Unit (25U TM00 750 GWA)STM-4 Aggregate Units (25U TM00 750 GSA, GSC, HVB)STM-1 Tributary Unit (25U JU00 750 GVA)

72 seconds: STM-1 Aggregate Unit (25U TM00 750 HWF)STM-1 Tributary Unit (25U TM00 750 HWE, HWG,NTKD11AA)

The initial delay before a laser restart pulse is dependent on the variant as follows:

72 seconds: STM-1 Aggregate Unit (25U TM00 750 GWA)

90 seconds: STM-1 Aggregate Unit (25U TM00 750 HWF)STM-1 Tributary Unit (25U TM00 750 HWE, HWG,NTKD11AA)

94 seconds STM-4 Aggregate Units (25U TM00 750 GSA, GSC, HVB)STM-1 Tributary Unit (25U JU00 750 GVA)

The longer initial delay allows for interactions between section ends if a fibre break occurs in one direction only.

The operation of the automatic laser shutdown for STM-1 Aggregate Unit 25U TM00 750 GWA, with reference to Figure 3-7, is described in the following paragraphs.



3

Figure 3-7Automatic laser shutdown operation

If a fibre break at point ‘X’ occurs, Terminal A raises an RS-LOS alarm which causes the laser at Terminal A to shutdown approximately 525 ms after the fibre breaks. Terminal B raises an RS-LOS alarm approximately 525 ms after the fibre breaks, this causes the laser at Terminal B to be shutdown 525 ms after the alarm is detected (i.e. approximately 1.05 seconds after the fibre break). Thus the optical power at the point ‘X’ is removed approximately 1.05 seconds after the fibre breaks.

Whilst the break is present, an automatic laser restart is attempted at Terminal A by removing the laser shutdown signal to the laser for 2 seconds every 62 seconds. The laser at Terminal A is switched on for 2 seconds which removes the RS-LOS alarm, and thus the laser shutdown signal, at Terminal B for 2 seconds. The laser at Terminal B is switched on for 2 seconds, however, the signal from the Terminal B does not reach Terminal A due to the fibre break. An RS-LOS is therefore still present at Terminal A after the 2 seconds restart signal and the laser shutdown signal is reapplied. This sequence is repeated every 64 seconds.

Once the break has been repaired, an automatic laser restart is performed at Terminal A, removing the laser shutdown signal to the laser for 2 seconds. The laser is switched on for 2 seconds which removes the RS-LOS alarm, and thus the laser shutdown signal, at Terminal B for 2 seconds. The laser at Terminal B is switched on which, as the break is fixed, removes the RS-LOS alarm at Terminal A and disables the laser shutdown signal.

The STM-4 Optical Aggregate Unit, STM-1 Optical Tributary Unit and the latest versions of the STM-1 Optical Aggregate Unit (variant 25U TM00 750 HWF) contain an ALS circuit which differs in operation from that described in the previous paragraphs in that the laser is also shutdown immediately if:

• STM-4 Optical Aggregate Unit: an OS-Optical_Power_Low and a OS-Laser_Bias_High condition (indicating failure of the laser back diode used by the feedback circuit on the optical transmitter module). If the shutdown is initiated by an OS_Optical_Power_Low/ OS-Laser_Bias_High alarm combination, the laser can not be restarted until the unit is reset.

TX

STM-1Aggregate Unit

TX

RX

RX

Terminal ‘A’ Terminal ‘B’

‘X’FibreBreak

STM-1Aggregate Unit



• STM-1 Optical Tributary Unit and STM-1 Optical Aggregate Unit (variant 25U TM00 750 HWF): a Clock Fail condition (dedicated ALS clock). If the shutdown is initiated by a Clock Fail condition, the laser can not be restarted until the unit is reset.

Laser test facilityThe following units provide a test facility which overrides the laser shutdown mechanism:

• latest versions of the STM-1 Optical Aggregate Units 25U TM00 750 GWA and 25U TM00 750 HWF (identifiable by a second yellow LED on the front panel)

• STM-1 Optical Tributary Unit

• STM-4 Optical Aggregate Unit

The override enables the laser for 90 seconds in order for optical power measurements to be made. For safety reasons, the laser shutdown override will not operate if an Optical High Power alarm is present. For details of the link options, see the Module Replacement Procedures, NTP 323-1061-547, or the Unit Descriptions, NTP 323-1061-110.



3

Engineering Order Wire operationThe EOW system uses a calling feature which uses the format ‘n n #’, where n is a digit between 0 and 9 and # is the dial termination character. The two ‘n’ digits provide a unique two-digit site-identification code which is set via a DIL switch on the EOW Unit. This code is used to match against the incoming DTMF digit sequence.

Selective calling of an individual site is made by taking the handset off-hook, waiting for a dialling tone and dialling the site-identification code followed by the dial termination character (i.e. ‘n n #’).

A group dialling and broadcast call feature is also provided by the use of the wild card character ‘*’ as follows:

• entering the sequence ‘* n #’ rings all sites ending with the ‘n’ digit (group call)

• entering the sequence ‘n * #’ rings all sites starting with the ‘n’ digit (group call)

• entering the sequence ‘* * #’ which will make all nodes ring (broadcast call)

The EOW Unit contains a green LED and a buzzer which indicates the status of the EOW system at that node as follows:

• LED and buzzer OFF - EOW channel not in use

• LED ON, buzzer OFF - EOW channel in use

• LED flashing, buzzer sounding - incoming EOW call

Note 1: There is no time-out for the LED and buzzer, they remain active until the call is answered (handset taken off-hook) or the caller’s handset is replaced.

Note 2: The LED at the node initiating an EOW call is not illuminated, this indicates that it is the node which configured the system.

If a path section is invalid (out of alignment), the communication path is disconnected. If working in a protected configuration (protected terminal or ring) and the communication path is broken, EOW communication is still possible to all multiplexers but it may be necessary to re-initialise the call (i.e. there is no automatic switching to protect to a call).

Note: If the communication path is re-established after a call has been re-initiated, it is possible that a ‘howl’ will be heard in the handset earpiece. If this occurs, the call must be re-initiated.

ConstructionThis section describes the mechanical construction of the Nortel TN-1X (see Figure 3-8) and TN-1X/S (see Figure 3-9) subracks.



Figure 3-8TN-1X unequipped subrack

Figure 3-9TN-1X/S unequipped subrack

EMCShielding

Backplane

CableAccess

CoverSlide/TiltMechanism

Local CraftAccess Panel

FibreRoutingTray

Plug-inUnitGuides

StationInterfaceArea

EMCShielding

Plug-in UnitGuides

Backplane

StationInterfaceArea



3

The design emphasis is placed upon compactness, accessibility, and ease of installation and maintenance. The basic plug-in unit is a printed circuit board assembly with three integral connectors at the rear edge which mate with those mounted on a subrack backplane. The traditional horizontal subrack assembly, with vertically mounted plug-in units, is used as it provides efficient ventilation by natural convection. The subrack is primarily intended for mounting in racks to draft ETSI standard pr ETS 300-119 part 3. If required, mounting kits will be available for mounting in BT Type 91, BT Type 92, and BT TEP 1E racks.

The subracks are formed from extruded aluminium side plates which are joined by cross rails of aluminium alloy extrusion. The cross rails provide mounting for the plug-in unit guides, and retention of EMC honeycomb shield material above and below the plug-in unit area. The front and rear cross rails have stainless steel coated steel nut bars for plug-in unit, backplane, and subrack rear cover retention. The lower sections of the side plates are cut away to allow cable access. Flanges are fastened to the side plates which have captive screws for mounting the subrack to the rack.

Front mounted flanges are standard for mounting to ETSI racks. Provision is made in the side plates for the attachment of a spigot to support the subrack during installation in certain rack types. The backplane is mounted on the rear rail and side plates.

Subrack backplaneThe subrack backplane is a one piece multilayer printed circuit board. The upper section has the plug-in unit connectors and the lower section the connectors for the Interface Modules.

Figure 3-10 shows the position of the plug-in unit connectors in the upper plug-in unit area of the TN-1X subrack backplane. Figure 3-11 shows the position of the Interface Module connectors in the lower station interface area of the backplane. Figure 3-12 shows the position of the plug-in unit connectors and Interface Module connectors on the TN-1X/S subrack backplane.

SK6 and SK7 are integrated circuit sockets which mount the integrated circuits (IC1 and IC2) that identify the Ethernet address.

Backplane connectorsThe plug-in unit/backplane connections are made via DIN 41612 (IEC 603-2) type connectors. All positions have upper (A) and lower (C) connectors for traffic, alarm, and control signals. The middle (B) connector is the power supply connector. All upper and lower connectors, except the two Power Units, are plugs on the backplane and sockets on the plug-in units. The Power Unit connectors are sockets on the backplane and plugs on the plug-in units (for safety reasons). All middle connectors are plugs on the backplane and sockets on the plug-in units. The middle power supply connectors have early earth extended pins.



Figure 3-10TN-1X subrack backplane - plug-in unit area

PLA

1P

LA6

PLA

11P

LA16

PLA

21P

LA26

PLA

34P

LA42

PLA

47P

LA52

PLA

57S

KA

62S

KA

71P

LA80

PLB

1P

LB6

PLB

11P

LB16

PLB

21P

LB26

PLB

34P

LB42

PLB

47P

LB52

PLB

57P

LB62

PLB

71P

LB80

PLC

1P

LC6

PLC

11P

LC16

PLC

21P

LC26

PLC

34P

LC42

PLC

47P

LC52

PLC

57S

KC

62S

KC

71P

LC80

IC2

IC1

SK

7

SK

6

ET

HE

RN

ET

AD

DR

ES

S



3

Figure 3-11TN-1X subrack backplane - station interface area

SK

D1

SK

D10

SK

D15

SK

D25

SK

D35

SK

D40

SK

D45

SK

D50

SK

D55

SK

D65

SK

D70

SK

D80

SK

E40

SK

E80

SK

D30

25Y

PB

5075

0GV

W

P1

P2

P3

P4



Figure 3-12TN-1X/S subrack backplane

PLA

1P

LA6

PLA

11P

LA16

PLA

21P

LA26

PLA

34P

LA42

PLA

47P

LA52

PLA

57S

KA

62S

KA

71P

LA80

PLB

1P

LB6

PLB

11P

LB16

PLB

21P

LB26

PLB

34P

LB42

PLB

47P

LB52

PLB

57P

LB62

PLB

71P

LB80

PLC

1P

LC6

PLC

11P

LC16

PLC

21P

LC26

PLC

34P

LC42

PLC

47P

LC52

PLC

57S

KC

62S

KC

71P

LC80

SK

E1

SK

G1

SK

D42

SK

F42

SK

D56

SK

F56

PLD

78

SK

F78

IC2

IC1

SK

7

SK

6

P1

P2

P3

P4

ET

HE

RN

ET

AD

DR

ES

S

25YPB50750HHY



3

The upper and lower connectors are fitted with key pegs which prevent a unit being inserted into the wrong backplane position.

The Interface Module/backplane connections are made via DIN 41612 (IEC 603-2) type connectors. On the TN-1X subrack, all positions have upper (D) connector. Subrack slot positions 40 and 80 also have lower (E) connectors. On the TN-1X/S subrack, two backplane connectors are mounted horizontally for each Interface Module, each SIM having two connectors and each TIM having a single connector (the extra connector on the backplane is provided for possible future functionality).

Backplane linksThe backplane contains four strapping pins, P1 to P4 (see Figure 3-11 and Figure 3-12). These pins should be left unstrapped.

Plug-in unitsAll plug-in units, irrespective of size, have an injection moulded face plate metalised on the rear face, and locking upper and lower levers for insertion/extraction from the subrack.

To maintain Electro-Magnetic Compatibility (EMC) protection, the front panels are fitted with spring fingers so that they form a continuous earth plane. Spare positions must be fitted with blank panels. For identification purposes each plug-in unit front panel is marked with its abbreviated name, Nortel 13-digit code, and bar code.

All units make contact with the subrack backplane via three connectors; a power connector in between upper and lower signal connectors. All external connections are made via Interface Modules in the SIA of the subrack, except those carrying the optical signals which connect directly to the front of the appropriate optical unit.

Interface modulesThe Interface Modules are reduced size cards that provide the external connections. The Interface Modules fit into the lower Station Interface Area (SIA) of the subrack, different types of Interface Modules are available to cater for different customer connector requirements.

The Interface Modules have an aluminium extrusion face plate, upper and lower levers for insertion/extraction from the subrack, and a single captive central locking screw.

To maintain EMC protection, the front panels are fitted with spring fingers so that they form a continuous earth plane. Spare positions must be fitted with blank panels. For identification purposes each Interface Module front panel is marked with its name, Nortel 13-digit code, and product change status level.

All units make contact with the subrack backplane via one or two connectors. External connector interfaces are mounted on the front panels and are selected to meets customer applications.



On the TN-1X subrack, the Interface Modules are located behind a moulded cover (see Figure 3-13) which is mounted on a slide and tilt mechanism. The cover contains two locking screws and two latches.

Figure 3-13Station interface area cover

EOW handsetIf the EOW facility is used at a TN-1X, a mounting bracket is fitted to the underside of the LCAP (see Figure 3-14) for the EOW handset. This holds the EOW handset when not is use. When the EOW is required, the EOW handset is removed from the bracket and plugged into the appropriate connector in the LCAP.

For the TN-1X/S, there is no convenient position for mounting an EOW handset. If the EOW facility is required, a DTMF handset can be plugged into the connector on the EOW/CATT connector panel.

S/DMS TransportNode

To Open

Lock Position

To Open

Lock Position

Locking screw(lock position)

Latch (closed position)



3

Figure 3-14EOW handset - TN-1X mounting position

Electro-Magnetic Compatibility protectionElectro-Magnetic Compatibility (EMC) protection is provided at subrack level. Nickel loaded solid silicone gaskets are used at critical openings, for example between the backplane and subrack rails at subrack level. Openings where air flow is essential for cooling purposes are covered with honeycomb shielding material, for example above and below the plug-in unit sections of the subracks.

Electro Static Discharge protectionElectro Static Discharge (ESD) protection is achieved by the provision of low resistance earth paths between the rack parts, subrack parts, and plug-in unit front panels to ensure any local discharge is conducted away to the installation earth. Discharge to the front face of plug-in units is prevented by use of non-conductive material on exposed faces.

An ESD bonding point for operator use is provided on the Local Craft Access Panel at the front of the TN-1X subrack. The racks may also be fitted with an ESD bonding points for operator use.

LCAP

FibreTray

EOWHandset

ServiceInterfaceArea



Earthing arrangementsThe rack is normally fitted with a common earth point at the top in the form of a copper bus bar or single fixing. The earth connection is distributed to the subracks either by means of individual wires in the form of twisted pairs (earth and d.c. power supply) or by a vertical copper bus bar with a short link wire to each subrack position on the right hand side of the rack.

Unused subrack positionsIn order to maintain EMC protection, all unused plug-in unit and Interface Module positions must be fitted with blank front panels. Codes for the relevant blank front panels are as follows:

Payload Manager ) 2 Mbit/s Tributary ) 1" Dummy Panel, 25R BN00 021 AABSTM-1 Tributary Unit )

STM-1 Aggregate Unit ) 1.6" Dummy Panel, 25R BN00 021 AACSTM-4 Aggregate Unit )

Power Unit - 1.8" Dummy Panel, 25R BN00 021 AAD

1" Interface Module - 1" Dummy Panel, 25R BN00 021 AAA

Thermal qualifications• A maximum of three TN-1Xs fitted with STM-1 aggregates can be

equipped per 2.2 m ETSI rack and will operate over the full ambient temperature range of -5°C to 45°C. No air gap is required between the subracks.

• Two TN-1Xs in a 2.2 m ETSI rack, both fitted with STM-4 aggregates, will operate over the full ambient temperature range of -5°C to 45°C if a 525 mm air gap is provided between the subracks.

• Two TN-1Xs in a 2.2 m ETSI rack, both fitted with STM-4 aggregates, will operate over the full ambient temperature range of -5°C to 35°C with no air gap between the subracks.

• Three TN-1Xs fitted with STM-4 aggregates per 2.2 m ETSI rack is not recommended.

• One TN-1X or one TN-1X/S, with any configuration of aggregates and tributaries, can be equipped in a Clifton or Quante street cabinet and will operate over the full ambient temperature range of -5°C to 45°C. The ambient temperature range of operation in other street cabinets will depend on the thermal performance of the cabinet.



3

InitialisationBefore powering-up, check that all the connectors have been correctly made, the required units fitted and the correct external power fuses inserted in the rack fuse holders.

Initial power-up sequenceNote: No changes should be made the multiplexer until at least 10 minutes after a power-up or reboot sequence.

Early Power Units do not contain an on/off switch and operate as soon as they are fully inserted into the subrack (assuming the station battery supply is present). When inserted into the subrack, the red ‘FAIL’ indicator on the Power Unit should not be lit.

Power Units 25U PW00 750 HSY contain a front panel ON/OFF switch. If a station supply is present when the Power Unit is inserted, the red ‘FAIL’ indicator will be lit. To power-up the subrack, set the switch to the ON position, the red ‘FAIL’ indicator on the front of the unit should go off.

Note: The ON/OFF switch must be set to the OFF position when inserting/removing the Power Unit.

When the Subrack Controller is powered-up for the first time, it performs a series of self-tests to verify the functionality of the various on-board devices. Whilst these tests are running, the red ‘FAIL’ indicator on Subrack Controller is lit. If a test fails which is catastrophic, the unit halts the start-up process. If any other test fails, the indicator flashes. The sequence is a number of flashes followed by a noticeably longer period with the indicator off, followed by another series of flashes. The sequence of flashes indicates which test has failed and can be interpreted as follows:

• 2 flashes - Random Access Memory (RAM) test failure

• 3 flashes - Multi-Function Peripheral (MFP) failure

• 4 flashes -High-level Data Link Controller (HDLC) failure

• 5 flashes - Local Area Network Controller Element (LANCE) failure

If all the tests are successfully concluded, the ‘FAIL’ indicator is extinguished. The Subrack Controller then checks for valid application code.

Note: Whilst the application code is being validated, the operator cannot login.

Once the application code is validated, the red and green LEDs on the LCAP or EOW/CATT Connector Panel go through a rapid on/off sequence and

CAUTIONLocal Terminal connectionDo not connect the CAT until the multiplexer has powered-up.



should then remain off. The ‘FAIL’ indicators on the traffic units are on momentarily during power-up and then remain off.

The red ALM P/D lamp on the Rack Alarm Unit (not applicable to the TN-1X/S) should go off. Once all the LEDs and lamps are extinguished, the system is ready for use.

Note: The LEDs on the LCAP and the traffic units may remain on if there are alarms present on the Nortel TN-1X.

ConfigurationOnce the Nortel TN-1X subrack is powered-up and the required application software is running, various parameters associated with the equipment should be configured via either the CAT or the element controller (see relevant NTP for details).

end of chapter


4-1

4

Traffic processing 4-This chapter provides information on traffic processing on the TN-1X and TN-1X/S.

Internal traffic interfacesThe Nortel TN-1X subrack (shelf) contains slot positions for the following units associated with traffic processing:

• six tributary units

— a maximum of four tributary units are used in present applications

Note: If the N+1 protection facility is required, an additional 2 Mbit/s Tributary Unit is fitted (not applicable to TN-1X/S subracks).

• two Payload Managers

• two aggregate units

Traffic connections between the traffic units are shown in Figure 4-1.

Each Payload Manager has a separate serial interface with each of the tributary units and aggregate units. Each interface consists of three lines in each direction, i.e. 155,520 kbit/s data, 155,520 kHz clock, and a Multiframe Synchronisation (MFS) signal.

The interface between the aggregate units consists of three lines for each of the three STM-1s in each direction, i.e. three 155,520 kbit/s data lines, three 155,520 kHz clock signals, and three MFS signals. These lines are only applicable for STM-4 aggregate units, when they allow AU-4 capacities to be transferred between the aggregate units.

The Multiframe Synchronisation signal, occurring every 48 frames (i.e. every 6 ms), is produced by the active Payload Manager and is used to ensure that payload connections between the Payload Manager and the interface units are clock and multiframe synchronous. The traffic units take account of any backplane transmission delays and delays caused by the serial/parallel conversions by using co-directional clocks and MFS signals for each data signal.


4-2 Traffic processing

Figure 4-1Inter-unit traffic connections

Data is transferred between the traffic units in variations of the STM-1 frame format as detailed in the following sections. Details of the Synchronous Digital Hierarchy (SDH) are given in Chapter 1.

Tributary Unit/Payload Manager interfacesThe logical interface between the Tributary Units and the Payload Manager is designed to allow the maximum flexibility for the allocation of tributary data into the transmission structure.

Between the Tributary Units and the Payload Managers, data is transferred in a partially filled secondary format. In this format, the TU data is packed into the STM-1 frame columns, starting at column one and occupying the normal section and line overhead columns, and containing no gaps. When the data from all the Tributary Units is combined on the Payload Manager, it is in a packed TU format and occupies the first 252 columns of the STM-1 frame (see Figure 4-2, which shows the payload made up of 63 TU-12s, each occupying four columns). The last 18 columns of the STM-1 are unused and contain fixed bits.

PayloadManager B

(Main)

AggregateUnit (A)

TributaryUnit

1

AggregateUnit (B)

TributaryUnit

6

CLK

MFS

Data

CLK

MFS

Data

CLK

MFS

Data

CLK

MFS

Data

CLK

MFS

Data

CLK

MFS

Data

CLK

MFS

Data

CLK

MFS

Data

3 3 3

CLK

MF

S

Dat

a

3 3 3

CLK

MF

S

Dat

a

STM-NSignals

STM-NSignals

NotesPayload Manager B has separate but identicallinks with the Tributary and Aggregate Units asPayload Manager A.Links between the two Aggregate Units are forSTM-4 working.

CLK: ClockMFS: Multiframe Synchronisation

PayloadManager A(Standby)


Traffic processing 4-3

4

Figure 4-2Tributary Unit/Payload Manager packed TU (secondary) format

The allocation of the TUs on the backplane interface is programmed on the Tributary Units in a fixed order, depending on the subrack position of the Tributary Unit, and are arranged as TUG-2s.

The allocation of tributary ports to TUs on the backplane is so as to fill the available TUGs in order (i.e. TUG number 0 first, followed by TUG number 1, etc). This allows the maximum number of free TUGs, with uncommitted TU types, which may be used by tributaries with other TU types.

Payload Manager/Aggregate Unit interfacesBetween the Payload Managers and the Aggregate Units, data is transferred in a floating AU (primary) format (see Figure 4-3). In this format, the data is in the form of an Administrative Unit Group (AUG), i.e. STM-1 frames with the section overhead bytes containing null bytes.

Figure 4-3Payload Manager/Aggregate Unit floating AU (primary) format

TU1COL 2

TU63COL 2

TU63COL3

TU1COL3

TU1COL4

TU63COL4

TU1COL1

TU63COL1

TU-12 Pointers

641 127 190 253 270

FixedStuff

9 261

VC4

POH

1

5

AU4 PTR

Payload

Null

Null

FixedStuff

3



Overhead busesThe Nortel TN-1X has a number of overhead buses, designated Overhead Bus (OHB) and Overhead Z Bus (OHZB). Access to these bytes is not available in present releases.

The buses are separated on unit type as follows:

• Aggregate positions have two buses

• Payload Manager positions have two buses

• Tributary positions have three buses

Each overhead bus operates at 4860 kbit/s and provides up to 75 timeslots, this gives a total bandwidth of 34,020 kbit/s of overhead or 75 x 7 timeslots.

Note: The bus actually provides 75 8-bit timeslots and a 7.5 bit timeslot and is reset every frame.

Traffic processingFigure 4-4 details the traffic processing for the Nortel TN-1X with 2 Mbit/s tributaries. Figure 4-5 details the traffic processing for the Nortel TN-1X with 34 Mbit/s tributaries. Figure 4-6 details the traffic processing for the Nortel TN-1X/4 with STM-1 tributaries. Figure 4-7 details the traffic processing for the Nortel TN-1X with mixed payloads (TU-12s and TU-3s).

Traffic processing for the Nortel TN-1X is performed by the following units:

• up to four 2 Mbit/s Tributary Units (TN-1X) or one 2 Mbit/s Tributary Unit (TN-1X/S). Each unit provides interfaces for sixteen 2048 kbit/s ports.

• up to four 34 Mbit/s Tributary Units (TN-1X). Each unit provides interfaces for a 34368 kbit/s port, providing access to sixteen 2048 kbit/s channels.

• up to four STM-1 Optical and Electrical Tributary Units (TN-1X) or up to four STM-1 Optical Tributary Units (TN-1X/S).

• one/two Payload Managers

• one/two STM-1 Optical or Electrical Aggregate Unitsorone/two STM-4 Optical Aggregate Unitsorone STM-1 Aggregate Unit and one STM-4 Aggregate Unit



4

Fig

ure 4-4

No

rtel TN

-1X traffi

c pro

cessing

(2 Mb

it/s tributaries)

bit/s

smit

face

bit/s

smit

face

bit/s

smit

face

bit/s

smit

face

SOH

Insert

AU

SyncSOH

Term

Opt

Elec

S

P

STM-1OptI/F

P

S

P

S

S

P

P

S

P

S

Opt

Elec

STM-1 Aggregate Unit B

STM-1ProcessorASIC

S

4

4

4

Sixteen

2048 kbit/s

HDB3

Outputs

Key:AU = Administrative UnitElec = ElectricalMux = MultiplexOpt = OpticalP = ParallelPOH = Path OverheadPTR = PointerS = SerialSOH = Section OverheadTerm = TerminationTSI = Timeslot InterchangerTU = Tributary UnitVC = Virtual Container

Note:Traffic processing is shown for Optical Aggregate Units. For Electrical Aggregate Units, the electro/optical conversions are replaced by CMI coding/decoding.

4
Nortel T
N-1X

System

Description

TU

PO

4 x 2 Mbit/s

ReceiveC-12

Map

TU

POH

Insert

TU

PO

4 x 2 Mbit/s

Receive

Interface

C-12

Map

TU

POH

Insert

TU

PO

4 x 2 Mbit/s

Receive

Interface

C-12

Map

TU

POH

Insert

TU

PO

4 x 2 Mbit/s

Receive

Interface

C-12

Map

TU

POH

Insert

TU

PO

4 x 2 M

Tran

Inter

C-12

Demap

TU

POH

Term

TU

PO

4 x 2 M

Tran

Inter

C-12

Demap

TU

POH

Term

TU

PO

4 x 2 M

Tran

Inter

C-12

Demap

TU

POH

Term

TU

PO

4 x 2 M

Tran

Inter

C-12

Demap

TU

POH

Term

TSI TSI

VCPOHInsert

Mux

TSITSI

TUSync

VCPOHTerm

AU

PTR

Term

SOH

Insert

AU

Sync

SOH

Term

Opt

Elec

AU

PTR

TUSync

VCPOHTerm

AU

PTR

Term

Mux

VCPOHInsert

AU

PTR

Insert

Opt

Elec

STM-1OptI/F

P

S

P

S

S

P

S

P

S

P

S

P

STM-1ProcessorASIC

STM-1 Aggregate Unit A Payload Manager (one of two, only one shown)

TSI ASIC

TSI ASIC

P S P S P S P S PP S

P S

S

P

2 Mbit/s Tributary Unit*

Quad 2 Mbit/s ASIC

4

4

4

Sixteen

2048 kbit/s

HDB3

Inputs 4

*TN-1X: One of four unitsTN-1X/S: One unit only


323-1

Fig

ure 4-5

No

rtel TN

-1X traffi

c pro

cessing

(34 Mb

it/s tributaries)

t

SOH

Insert

AU

Sync

SOH

Term

Opt

Elec

S

P

STM-1OptI/F

P

S

P

S

S

P

P

S

P

S

Opt

Elec

STM-1 Aggregate Unit B

STM-1ProcessorASIC

S

34368 kbit/s

HDB3

Output

Key:AU = Administrative UnitDemux = DemultiplexerElec = ElectricalMux = MultiplexOpt = OpticalP = ParallelPOH = Path OverheadPTR = PointerS = SerialSOH = Section OverheadTerm = TerminationTSI = Timeslot InterchangerTU = Tributary UnitVC = Virtual Container

Note:Traffic processing is shown for Optical Aggregate Units. For Electrical Aggregate Units, the electro/optical conversions are replaced by CMI coding/decoding.

bit/s

Mbit/s

ux

061-100 Release 7 S


TU

PO

34 Mbit/s

to 2 Mbit/s

Demux

C-12

Map

TU

POH

Insert

TU

PO

C-12

Map

TU

POH

Insert

TU

PO

C-12

Map

TU

POH

Insert

TU

PO

C-12

Map

TU

POH

Insert

TU

PO4

TU

POH

Term

TU

PO

C-12

Demap

TU

POH

Term

TU

PO

C-12

Demap

TU

POH

Term

TU

PO

C-12

Demap

TU

POH

Term

TSI TSI

VCPOHInsert

Mux

TSITSI

TUSync

VCPOHTerm

AU

PTR

Term

SOH

Insert

AU

Sync

SOH

Term

Opt

Elec

AU

PTR

Inser

TUSync

VCPOHTerm

AU

PTR

Term

Mux

VCPOHInsert

AU

PTR

Insert

Opt

Elec

STM-1OptI/F

P

S

P

S

S

P

S

P

S

P

S

P

STM-1ProcessorASIC

STM-1 Aggregate Unit A Payload Manager (one of two, only one shown)

TSI ASIC

TSI ASIC

P S P S P S P S PP S

P

S

S

P

34 Mbit/s Tributary Unit*

Quad 2 Mbit/s ASIC

34368 kbit/s

HDB3

Input

*TN-1X: One of four units

2 M

to 34

M

4

4

4

4

4

4

4

C-12

Demap


4

Figure 4-6Nortel TN-1X/4 traffic processing (STM-1 tributaries)

SO

H

Inse

rt

AU

Syn

cS

OH

Term

Opt

Ele

c

Opt Ele

c

ST

M-4

Opt

ical

I/F

P S P S

S P S P

ST

M-1

Pro

cess

or

AS

IC (

x4)

ST

M-4

Ag

gre

gat

e U

nit

A

Pay

load

M

anag

er(o

ne

of

two

, o

nly

on

e sh

ow

n)

Key

:A

U =

Adm

inis

trat

ive

Uni

tD

is =

Dis

inte

rleav

erE

lec

= E

lect

rical

Int =

Inte

rleav

erO

pt =

Opt

ical

P =

Par

alle

lP

OH

= P

ath

Ove

rhea

dS

= S

eria

lS

OH

= S

ectio

n O

verh

ead

Term

= T

erm

inat

ion

TS

I = T

imes

lot I

nter

chan

ger

Byt

e

Dis

int

Byt

e

Int

P SP SP S P S P S P S

SO

H

Inse

rt

AU

Syn

cS

OH

Term

Opt

Ele

c Opt

Ele

c

ST

M-4

Opt

ical

I/F

ST

M-1

Pro

cess

or

AS

IC (

x4)

Byt

e

Dis

int

Byt

e

Int

S P

ST

M-4

Pro

cess

or

AS

IC

ST

M-4

Pro

cess

or

AS

IC

ST

M-1

Tri

buta

ry U

nit

*

See

Fig

ure

4-4

for

deta

ils o

f tra

ffic

proc

essi

ng

S P S P S P S P S P S P S P

P S P S

Opt Ele

c

S P

AU

Syn

c

SO

H

Term

RX

TS

I

P S

SO

H

Inse

rt

Opt

Ele

c

ST

X

TS

I

P S

ST

M-1

Pro

cess

or

AS

IC

ST

M-1

Opt

ical

I/F

ST

M-4

Ag

gre

gat

e U

nit

B

No

te:

Traf

fic p

roce

ssin

g is

sho

wn

for

ST

M-1

O

ptic

al T

ribut

ary

Uni

t. F

or S

TM

-1

Ele

ctric

al T

ribut

ary

Uni

t, th

e el

ectr

o/op

tical

con

vers

ions

are

rep

lace

d by

C

MI c

odin

g/de

codi

ng.

* One

of f

our

units



Figure 4-7Nortel TN-1X traffic processing (mixed payloads)

TS

IT

SI

VC

PO

HIn

sert

Mux

TS

IT

SI

TU

Syn

c

VC

PO

HTe

rm

AU

PT

R

Term

AU

PT

R

Inse

rt

TU

Syn

c

VC

PO

HTe

rm

AU

PT

R

Term

Mux

VC

PO

HIn

sert

AU

PT

R

Inse

rt

ST

M-1

Opt

I/F

P S

P S

S P

S PPay

load

Man

ager

(o

ne

of

two

, on

ly o

ne

show

n)

TU

-12

TS

I AS

IC

PS

PS

PS

PS

PS

PS

Key

:A

U =

Adm

inis

trat

ive

Uni

tE

lec

= E

lect

rical

Mux

= M

ultip

lex

Opt

= O

ptic

alP

= P

aral

lel

PO

H =

Pat

h O

verh

ead

PT

R =

Poi

nter

S =

Ser

ial

SO

H =

Sec

tion

Ove

rhea

dTe

rm =

Ter

min

atio

nT

SI =

Tim

eslo

t Int

erch

ange

rT

U =

Trib

utar

y U

nit

VC

= V

irtu

al C

onta

iner

No

te:

Traf

fic p

roce

ssin

g is

sho

wn

for

Opt

ical

Agg

rega

te U

nits

. For

E

lect

rical

Agg

rega

te U

nits

, the

el

ectr

o/op

tical

con

vers

ions

are

re

plac

ed b

y C

MI c

odin

g/de

codi

ng.

ST

M-1

Tri

buta

ry U

nit

*

Opt Ele

c

S P

AU

Syn

c

SO

H

Term

P S

SO

H

Inse

rt

Opt

Ele

c

S P

P S

ST

M-1

Pro

cess

or

AS

IC

ST

M-1

Opt

ical

I/F

TU

-3 T

SI A

SIC

*

TU

-3 T

SI A

SIC

*

TU

-12

TS

I AS

IC

TU

G-3

AD

D

Mux

TU

G-3

AD

D

Mux

RX

TS

I

TU

-12 TU

-3

TX

TS

I

TU

-12 TU

-3

TU

G-3

AD

D

Mux

ST

M-1

A

gg

reg

ate

Un

it

See

Fig

ure

4-4

for

deta

ils o

f tr

affic

pr

oces

sing

ST

M-1

A

gg

reg

ate

Un

it

See

Fig

ure

4-4

for

deta

ils o

f tr

affic

pr

oces

sing

ST

M-1

Opt

I/F

* P

roce

ssin

g fo

r TU

-3 T

SI A

SIC

is

the

sam

e as

for T

U-1

2 T

SI

AS

IC b

ut a

t the

TU

-3 le

vel.

*One

of f

our

units

Mux



4

2 Mbit/s Tributary UnitEach 2 Mbit/s Tributary Unit can process up to sixteen 2048 kbit/s High Density Bipolar 3 (HDB3) tributary signals as follows:

Tributary to Payload Manager directionEach HDB3 tributary input is converted to binary format and asynchronously mapped into a VC-12 as defined in ITU-T recommendation G709.

The VC-12 is combined with the parts of the TU-12 having a fixed position in the synchronous frame (bytes V1 to V4 containing the pointer information which is used to locate the start of the VC-12).

Each TU-12 is allocated four columns in the STM-1 frame. Data for each of the TU-12s is combined in a partially filled secondary frame format (see “Tributary Unit/Payload Manager interfaces” on page 4-2), containing no section overhead. The partially filled secondary frames are converted to serial form at 155,520 kbit/s and output via separate backplane interfaces to the main and standby Payload Managers (if appropriate).

Payload Manager to tributary directionSerial data at 155,520 kbit/s in a partially filled secondary frame format is received from the main and standby Payload Managers (if appropriate). Selection of either the main or standby signal is controlled by the Subrack Controller. The selected signal is converted to parallel form and the data separated into the individual TUs.

For each TU, the pointer value is extracted from the V1 and V2 bytes and used to locate the start of the VC-12. The control and overhead bits are removed from the VC-12 and processed.

The data is then demapped and converted to HDB3 form for output to the backplane connectors.

34 Mbit/s Tributary UnitEach 34 Mbit/s Tributary Unit can process a single plesiochronous 34368 kbit/s High Density Bipolar 3 (HDB3) tributary signal as follows:

Tributary to Payload Manager directionEach HDB3 tributary input is converted to binary format and demultiplexed (according to ITU-T recommendation G.742 and G.751) into its constituent sixteen 2048 kbit/s signals. Each 2048 kbit/s signal is asynchronously mapped into a VC-12 as defined in ITU-T recommendation G709.

The VC-12 is combined with the parts of the TU-12 having a fixed position in the synchronous frame (bytes V1 to V4 containing the pointer information which is used to locate the start of the VC-12).

Each TU-12 is allocated four columns in the STM-1 frame. Data for each of the TU-12s is combined in a partially filled secondary frame format (see “Tributary Unit/Payload Manager interfaces” on page 4-2), containing no section overhead. The partially filled secondary frames are converted to serial



form at 155,520 kbit/s and output via separate backplane interfaces to the main and standby Payload Managers (if appropriate).

Payload Manager to tributary directionSerial data at 155,520 kbit/s in a partially filled secondary frame format is received from the main and standby Payload Managers (if appropriate). Selection of either the main or standby signal is controlled by the Subrack Controller. The selected signal is converted to parallel form and the data separated into the individual TUs.

For each TU, the pointer value is extracted from the V1 and V2 bytes and used to locate the start of the VC-12. The control and overhead bits are removed from the VC-12 and processed. The VC-12 signal is then demapped into a 2048 kbit/s signal.

The sixteen 2048 kbit/s signals are then multiplexed and converted to HDB3 form for output to the backplane connectors.

STM-1 Tributary UnitEach STM-1 Tributary Unit can process up to sixty-three VC-12 signals or, for mixed payload STM-1 Tributary Units, three VC-3 signals (or a combination of VC-12s and VC-3s) as follows:

Note: Although the user interface allows the user to change the path trace settings for STM-1 Tributary Units 25U JU00 750 GVA/GVB and 25U TM00 750 HWE, the path trace is fixed to the default setting on the unit and cannot be changed.

Tributary to Payload Manager directionOn the STM-1 Optical Tributary Unit, the incoming 155,520 kbit/s optical signal is applied to the optical receiver on the optical transceiver. Opto-electrical conversion is performed by a germanium Avalanche Photodiode (APD). The signal is then amplified and regenerated. The circuit includes a limiting amplifier which ensures that the optimum ‘eye’ waveform is always present irrespective of the amplitude of the optical input signal (allowing for different route lengths).

On the STM-1 Electrical Tributary Unit, the incoming 155,520 kbit/s CMI encoded signal is decoded into a binary signal by the electrical transceiver.

The data from the optical transceiver (STM-1 Optical Tributary Unit) or the electrical transceiver (STM-1 Electrical Tributary Unit) is converted to parallel form and applied to the STM-1 Processor. The data is frame aligned, descrambled, and the SOH bytes extracted and processed. The AU-4 payload is realigned to the local frame synchronisation signal and new AU pointers generated.



4

The AU-4 payload is applied to the TU-12 RX Timeslot Interchanger (TSI) where:

• The AU-4 pointer information is extracted and used to locate the start of the VC-4. The VC-4 path overhead data is terminated and processed.

• The TU-12 s are synchronised by realigning the TU-12s to the local multiframe and generating new TU pointers.

• TU-12 data is written into each TSI in sequential order but can be read in any order, thus providing a re-ordering opportunity.

• The reordered TU-12s, in a partially filled secondary format (see ‘Tributary Unit/Payload Manager interfaces’ on page 4-2).

For mixed payload STM-1 Tributary Units, the AU-4 payload is also applied to the TU-3 RX TSI (in parallel with the TU-12 RX TSI) where the above processing occurs at the TU-3 level. The outputs of the TU-3 RX TSI and the TU-12 RX TSI are combined to form the VC-4 payload.

The output from the RX TSI(s) is converted to serial form at 155,520 kbit/s and output via separate backplane interfaces to the main and standby Payload Managers (if appropriate).

Payload Manager to tributary directionSerial data at 155,520 kbit/s in a partially filled secondary frame format is received from the main and standby Payload Managers (if appropriate). Selection of either the main or standby signal is controlled by the Subrack Controller. The selected signal is converted to parallel form and applied to the TU-12 TX TSI and the TU-3 TX TSI (mixed payloads STM-1 Tributary Units only). The selected signal is then processed as follows:

• For TU-12 only STM-1 Tributary Units, the TU-12 TX TSI reorders the TU-12s as required, assembles the VC-4, and generates the VC-4 path overhead. The data is then applied to the STM-1 Processor Unit.

• For mixed payload STM-1 Tributary Units, the TU-12 TX TSI reorders the TU-12s as required, assembles the VC-4, and generates the VC-4 path overhead. The TU-3 TX TSI performs the same function at the TU-3 level. The outputs from the TU-12 TX TSI and the TU-3 TX TSI are then multiplexed together to form the VC-4 payload. The VC-4 path overhead and AU-4 pointer is regenerated as required. The data is then applied to the STM-1 Processor Unit.

The SOH bytes are generated and inserted into the appropriate positions within the STM-1 frame and the resulting data scrambled. The scrambled data is converted to serial form and applied to the optical transceiver (STM-1 Optical Tributary Unit) or the electrical transceiver (STM-1 Electrical Tributary Unit).

On the STM-1 Optical Tributary Unit, the optical transceiver performs the electro-optic conversion on the scrambled serial data. This is achieved using a modulated semiconductor laser. The mean output of the laser is stabilised at a nominal -2.5 dBm (long haul) or -10 dBm (short haul) by a feedback circuit.



The short haul option is only available on the latest units (variant 25U TM00 750 HWE/HWG) and is selected via an on-board link.

On the STM-1 Electrical Tributary Unit, the electrical transceiver performs the CMI coding on the scrambled serial data.

Payload ManagerThe Nortel TN-1X subrack contains slot positions for two Payload Managers. When two units are fitted, the units operate in a main/standby configuration. In normal operation both units are active but the outputs of the standby unit are disabled. Disabling/enabling of the required outputs is controlled by the Subrack Controller.

The Payload Manager provides a drop and insert and a re-ordering facility at the TU level between the aggregate and tributary interface units. For mixed payload Payload Managers, this re-ordering is performed at both the TU-12 and TU-3 levels by separate TSI ASICs.

In each direction:

• Data from the aggregate unit in a floating AU primary format (see “Payload Manager/Aggregate Unit interfaces” on page 4-3) is converted from serial to parallel form. The AU-4 pointer information is extracted and used to locate the start of the VC-4. The VC-4 path overhead data is terminated and processed.

• The TUs are synchronised by realigning the TUs to the local multiframe and generating new TU pointers.

• The TUs are reordered, if required, using TSIs. Two TSIs are used, one provides the insert facility and one provides the drop facility. TU data is written into each TSI in sequential order but can be read in any order, thus providing a re-ordering opportunity.

• The order in which the TUs are read from the TSIs is controlled by a store under control of the Subrack Controller.

• In a drop and insert configuration, the traffic bytes of the required TUs from the insert TSI are combined with the through-path TUs from the TU synchroniser to provide the TU ordering. In a terminal configuration, the insert TSI provides all the TUs.

• TUs that are to be dropped (all TUs in the case of a terminal configuration) are output onto a common data bus. The TUs are output in serial form to each Tributary Unit, in a partially filled secondary format (see ‘Tributary Unit/Payload Manager interfaces’ on page 4-2), as required.

• The VC-4 path overhead bytes are generated and combined with the combined data from the TSI and the TU synchroniser. An AU-4 pointer is then added (set to its nominal value of 522).

When using mixed payloads, the above processing is performed at both the TU-12 and TU-3 level. The outputs from the TU-12 TSI ASIC and the TU-3 TSI ASIC are multiplexed together to form the VC-4 payload. The VC-4 path overhead and AU-4 pointer is regenerated as required.



4

The resulting data is converted to serial form for transmission to the aggregate units.

STM-1 Aggregate UnitThe Nortel TN-1X subrack contains slot positions for two aggregate units with optical or electrical STM-1 interfaces. When two units are fitted, the two aggregate ports, A and B, are used in either a main/standby mode for a 1 for 1 protected terminal multiplexer, or as separate east and west ports for a drop and insert multiplexer. A single unit can be used to provide an unprotected terminal multiplexer. See “TN-MS Element Controller for TN-1” on page 2-4.

The STM-1 Aggregate Unit provides the optical or electrical transmit and receive interfaces and also generates/terminates the Section Overhead (SOH) of the STM-1 frames. The unit contains a reordering facility at the AU-3 level of the SDH but this is not used in present applications.

Payload Manager to STM-1 directionSerial data at 155,520 kbit/s, in a floating AU primary format (see “Payload Manager/Aggregate Unit interfaces” on page 4-3), is received from the main and standby Payload Managers (if appropriate). Selection of either the main or standby signal is controlled by the Subrack Controller. The selected signal is converted to parallel form.

The SOH bytes are generated and inserted into the appropriate positions within the STM-1 frame and the resulting data scrambled. The scrambled data is converted to serial form and applied to the optical transceiver (STM-1 Optical Aggregate Unit) or the electrical transceiver (STM-1 Electrical Aggregate Unit).

On the STM-1 Optical Aggregate Unit, the optical transceiver performs the electro-optic conversion on the scrambled serial data. This is achieved using a modulated semiconductor laser. The mean output of the laser is stabilised at a nominal –2.5 dBm (long haul) or -10 dBm (short haul) by a feedback circuit. The short haul option is only available on the latest units (variant 25U TM00 750 HWF) and is selected via an on-board link.

On the STM-1 Electrical Aggregate Unit, the electrical transceiver performs the CMI coding on the scrambled serial data.

STM-1 to Payload Manager directionOn the STM-1 Optical Aggregate Unit, the incoming 155,520 kbit/s optical signal is applied to the optical receiver on the optical transceiver. Opto-electrical conversion is performed by a germanium Avalanche Photodiode (APD). The signal is then amplified and regenerated. The circuit includes a limiting amplifier which ensures that the optimum ‘eye’ waveform is always present irrespective of the amplitude of the optical input signal (allowing for different route lengths).

On the STM-1 Electrical Aggregate Unit, the incoming 155,520 kbit/s CMI encoded signal is decoded into a binary signal by the electrical transceiver.



The data from the optical transceiver (STM-1 Optical Aggregate Unit) or the electrical transceiver (STM-1 Electrical Aggregate Unit) is converted to parallel form and applied to the STM-1 Processor. The data is frame aligned, descrambled, and the SOH bytes extracted and processed. The AU-4 payload is realigned to the local frame synchronisation signal and new AU pointers generated. The AU-4 payload, in a floating AU primary format, is converted to serial form and output to the Payload Managers.

STM-4 Optical Aggregate UnitThe TN-1X/4 multiplexer subrack contains slot positions for two Aggregate Units which operate as separate A and B ports in a drop and insert mode.

Note: It is possible to operate with one STM-4 Aggregate Unit and one STM-1 Aggregate Unit.

The STM-4 Optical Aggregate Unit provides the optical transmit interfaces, generates/terminates the Section Overhead (SOH) and drops/inserts one of the AUGs within the STM-4 signal.

Tributary to STM-4 directionThe STM-4 signal has the capacity for four AUG (STM-1) payloads. In the transmit direction, one of the AUGs (selectable via the local terminal or the network management system) is supplied from either the main or standby Payload Manager. Selection of either the main or standby signal is controlled by the Subrack Controller. The remaining three AUG payloads are received from the other STM-4 Optical Aggregate Unit in the subrack. Each AUG payload is received as serial data at 155,520 kbit/s in the primary format. The selected four AUG signals are converted to parallel form.

The SOH bytes are generated and inserted into STM-1 #1 (the SOH is actually inserted into all four STM-1 signals but some of the SOH bytes in STM-1 #2, #3 and #4 are ignored in the receive direction). The four STM-1 payloads are scrambled and byte interleaved. The framing bytes in the resulting STM-4 signal are overwritten (to maintain alignment if one of the STM-1 processors fails). A BIP-8 calculation is then performed on the entire STM-4 frame, scrambled and placed in the SOH (Byte B1) of STM-1 #1 of the next frame.

Note: Although the scrambling is performed at the STM-1 level, the required STM-4 scrambling according to ITU-T recommendations is achieved.

The STM-4 data is converted to serial form at 622,080 kbit/s and applied to the optical transmitter module. The electro-optic conversion is performed by a modulated semiconductor laser. The mean output of the laser is stabilised at a nominal –0.5 dBm (long haul) or –11 dBm (intra-office) by a feedback circuit. The transmitter module contains a Peltier heater/cooler which keeps the module at the optimum operating temperature.



4

STM-4 to tributary direction.The incoming 622,080 kbit/s optical signal is applied to the optical receiver module. Opto-electrical conversion is performed by a III-V APD. The receiver module includes the circuitry to provide the necessary amplification, clock extraction and data retiming. The module ensures that the optimum ‘eye’ waveform is always present irrespective of the amplitude of the optical input signal (allowing for different route lengths).

The data from the optical receiver is converted to parallel form and applied to the STM-4 Processor. The data is frame aligned and disinterleaved. The resulting four STM-1 signals are applied to the STM-1 Processors where the data is descrambled and the SOH is extracted from the STM-1 payloads.

Note: Some of the SOH bytes of STM-1 #2, #3 and #4 are ignored in the receive direction.

In each STM-1 Processor, the AU payload is realigned to the local frame synchronisation signal and new AU pointers generated. The four AU payloads from the STM-1 Processors are converted to serial form. The selected AUG to be dropped is output to the main and standby Payload Managers in a floating AU primary format. The remaining AUGs, in a floating AU primary format, are applied to the other STM-4 Optical Aggregate Unit.

end of chapter


5-1

5

Equipment management 5-The equipment management functions of the Nortel TN-1X are performed by the Subrack Controller.

Backplane interfacesThe Nortel TN-1X subrack contains two backplane buses used for equipment management purposes (see Figure 5-1).

The control bus is used for transferring control and monitoring information between the Subrack Controller and the other plug-in units. The data communication bus is used for transferring the Embedded Control Channel (ECC) data between the aggregate units/STM-1 tributary units and the Subrack Controller. The ECC is provided by the Regenerator Data Communications Channel (DCCR), D1 to D3 bytes, or the Multiplexer Section Overhead (DCCM), D4 to D12 bytes, in the section overhead of the STM-1 frame.

Both the control and data communication buses are High-level Data Link Control (HDLC) based and conform to the proprietary Multi-Master Serial Bus (MMSB) standard. Backplane interfaces are at ‘Futurebus’ levels.

The control bus (MMSB1) operates at a nominal 2048 kbit/s, the clock being provided by the Subrack Controller which also derives the +2 V supply used for backplane termination of the data and clock buses. The data and clock buses of the control bus are terminated via resistors to the +2 V supply on the subrack backplane.

The data communication bus (MMSB2) operates at a nominal 1944 kbit/s, the clock being provided by one of the aggregate units. The aggregate units also derive a +2 V supply used for terminating the data and clock buses.

The Subrack Controller produces an update signal, synchronised to the Multiframe Synchronisation (MFS) signal from the Payload Managers, which is used for synchronising changes in configuration on the aggregate units. The update signal, which occurs 24.5 ± 0.25 frames after a MFS pulse, is activated once the new configuration data has been loaded onto the required aggregate units.


5-2 Equipm

ent managem

ent

323-1

Fig

ure 5-1

Eq

uip

men

t man

agem

ent bu

s architectu

re

l//ECC

SubrackController

+2 V

Timer

HDLCI/Fs

SubrackI/Fs

RackAlarm

I/F

RS232CI/F

EthernetI/F

Memory

µPLine Line

NetworkManage-mentSystem

LocalTerminal

RackAlarmBus

ory

ExternalAlarms

AlarmDetection & Protection


(SIM Type 41or

SIM Type 41S)

061-100 Release 7 S


HDLCInterfaces

Memory

Micro-cont

Control/MonitoringTributary Unit 1

Tributary Unit 2

Tributary Unit 3

Tributary Unit 4

CardController

ControMonitoringAggregate Unit A

+2 V

Aggregate Unit B

Control Bus (MMSB1)

Control Bus Clock

Control Bus 2 V

Data Comms Bus (MMSB2)

Data Comms Clock

Common 2 V

UpdateTerminations Terminations

HDLCInterfaces

Memory

Micro-cont

Control/Monitoring

CardController

Payload Manager A

Payload Manager B

HDLCInterfaces

Mem

Micro-cont

CardController

*Only two Tributary Units are used on the TN-1X/S.

Equipment management 5-3

5

Subrack ControllerThe Subrack Controller performs the general control and monitoring function for the Nortel TN-1X. The unit provides the following interfaces:

• two MMSB channels used for inter-unit communication (i.e. the control and data communication buses).

• Ethernet Attachment Unit Interface (AUI) for communication with the Element Controller via the Local Area Network (LAN).

• RS232C port for communication with a local terminal.

• standard alarm interface to a rack alarm bus (not supported on the TN-1X/S subrack).

• general purpose subrack interface (e.g. unit removal alarms, power fail signals, external alarm inputs (see “External alarms” on page 5-6).

The Subrack Controller is based on a 32-bit 68020 microprocessor operating at 12.5 MHz and uses the pSOS+ operating system.

The Subrack Controller is provided with the following memory:

• 128 Kbytes of Flash EEPROM (Bank 0) which provides non-volatile non-erasable memory for the operating system and hardware/software initialisation code (i.e. the ‘foundation’ software).

• 4096 Kbytes of Flash EEPROM, arranged in two banks (Banks 1 and 2), for storing two versions of applications software, the default configuration data, and the download traffic unit software. Banks 1 and 2 can be downloaded via the user interface. The download traffic unit software is downloaded to the traffic units via the control bus (MMSB1).

• 2048 Kbytes of RAM used for basic microprocessor data and stack functions.

• 128 Kbytes of battery backed RAM used for storing the configuration data.

• Dual port RAM used for communication between the Ethernet interface and the microprocessor.

When the microprocessor ‘boots’ up, the microprocessor vectors to the foundation software, but performs a check to see if other downloaded modules exist in Banks 1 and 2 (see “Software” on page 5-15).

The unit incorporates a function self-check facility to check for hardware and software failures and also includes a real time clock function.

Card controllersEach traffic unit contains a microprocessor based ‘card controller’ circuit based on a 80C188 microcontroller operating at 10 MHz. The circuit monitors and controls other circuits on the unit under general direction of the Subrack Controller.


5-4 Equipment management

The circuit comprises the following basic components:

• An 80C188 microcontroller, which provides the required memory and peripheral select lines.

• A self test circuit which provides a non-maskable interrupt to the microcontroller if a failure occurs (watchdog timer time out or attempted writes to protected memory locations). If this interrupt is not successfully actioned, a reset is applied to the microcontroller.

• 128 Kbytes of EEPROM used for storing embedded software (foundation software). This memory contains the pSOS operating system, the hardware/software initialisation code and the MMSB communication code.

• 256 Kbytes of Random Access Memory (RAM) used for storing various data items and as a store for applications software downloaded from the Subrack Controller.

• An 82525 High Level Serial Communications Controller (HSCC) which provides the two MMSB channels.

Real time clockThe Subrack Controller contains a non-volatile real time clock with an accuracy of 1.25 seconds per day. The clock is used for time stamping alarm and performance messages. The clock is factory set but can be adjusted from the CAT or the Element Controller. When connected to a Element Controller, the clock is periodically adjusted to keep the local clock aligned with the Element Controller clock.

The real time clock function has a battery back-up which maintains time and calendar functions for up to approximately six weeks in the absence of power to the Subrack Controller.



5

Alarm monitoringThe Subrack Controller receives alarm information from the traffic units via the control bus. The received information is time-stamped, logged and processed as described in the following sections.

Details of the alarm indications, alarm sequences and individual alarms are given in the Alarm Clearing Procedures, NTP 323-1061-543.

Alarm handlingAlarm monitoringEach alarm is processed to convert the raw state of the alarm into a monitored alarm state (active or clear). For some alarms (where specific equipment/network applications need to be considered), the user can enable or disable the monitored alarm state. If alarm monitoring is disabled, the alarm will never be reported.

All reported alarms are time stamped and logged. Alarms are logged when the alarm state changes.

Alarm filteringEach alarm raised is subject to filtering which determines the alarm state. The alarm ‘present’ and alarm ‘not-present’ filtering periods are assigned pre-set values which cannot be changed. An alarm may therefore exist in one of three states:

• Present - an alarm that is present for longer than the ‘present’ filtering period (i.e. alarm is constant).

• Clear - an alarm that has cleared for longer than the ‘not-present’ filtering period.

• Masked - as the ‘Present’ state but is not reported due to the presence of a higher priority alarm.

Alarm maskingThis is performed by the Subrack Controller, so that all consequential alarms are suppressed and only the highest level alarm is included in the reporting schemes. Masking is subject to masking check and masking extension periods. The masking check period is the length of time during which the Subrack Controller checks to see if a higher level alarm is present before reporting an alarm. The masking extension period is the length of time during which the Subrack Controller waits to see if the clearing of a higher level alarm results in the clearance of a previously masked alarm. Any alarm that becomes masked is reported to the user interface as clear. Details of the masking hierarchy are given in the Alarm Clearing Procedures, NTP 323-1061-543.

Rack alarm categories/alarm severitiesEach of the generic alarms is allocated one of four rack alarm categories:

• Prompt - an alarm that requires immediate attention at all times. It is normally extended to a maintenance/control point when the station is unattended.



• Deferred - an alarm that does not require immediate attention outside normal hours. It is normally extended to a maintenance/control point when the station is unattended.

• In Station - an alarm that does not require attention outside normal hours. It is not normally extended.

• Disconnected - an alarm that is indicated by the user interface but no unit, subrack, or rack alarm indications or extensions are provided.

The rack alarm categories are linked to the alarm severities used by the Element Controller which displays alarm counts according to their severity. The alarm severities are Critical, Major, Minor or Warning and are linked to the rack alarm categories as follows:

Critical Prompt Major DeferredMinor In-stationWarning Disconnect

It is possible to change the rack alarm categories/severities of the alarms using the user interface.

Note: Certain alarms (Power Fail and Optical Power High) have fixed rack alarm categories.

All reported alarms are time stamped and logged. Alarms are logged when the alarm state changes.

External alarmsThe Flexible Access Module (variant 25U JJ00 750 HPD) and External Alarm Module support 5 external alarm input signals, provided as earth free relay contacts, which can be used for external alarm applications (e.g. door open, intruder alert, fire alert). Each alarm can be assigned a 15 character name via the UI to simplify identification.

Each alarm input is a closed contact input, i.e. floating inputs with no earth provided. Each alarm input is protected against accidental connection to a steady state voltage up to 72 V. Sensing circuits for each alarm detect open circuit (>1 MΩ) and short circuit (<200 Ω) conditions.

Provision is made via the user interface to set the operating mode of each alarm as follows:

• Off - disables monitoring of the alarm

• Closed - enables the monitoring of the alarm with the short circuit (<200 Ω) state being the active alarm condition. This is the default mode.

• Open - enables the monitoring of the alarm with the open circuit (>1 MΩ) state being the active alarm condition.



5

Filtering for the each alarm can be turned on and off (default) via the user interface. With filtering off, the alarm is raised immediately the active alarm condition is met. With filtering on, the alarm is not raised unless it is present for greater than a set filter period (i.e. transient alarms are ignored).

CAUTIONSIM Type 41and SIM Type 41S removal/insertionSpurious alarms may result if the Flexible Access Module (variant 25U JJ00 750 HPD) or the External Alarm Module is removed or inserted whilst monitoring of external alarms is enabled, but this action shall not cause loss of service or damage to equipment.

The Flexible Access Module (variant 25U JJ00 750 HPD) or the External Alarm Module must not be inserted into an operating multiplexer with the external alarm connector already fitted.

Electrical protectionThe Flexible Access Module (variant 25U JJ00 750 HPD) and External Alarm Module inputs provide connection against connection to a battery supply in the range of 40 V to 72 V, no protection is provided for battery surge, lightening pulse or mains voltages. All external equipment connected to the alarm inputs should provide protection from mains voltages in accordance with the requirements of EN 41003 for connection to Telecommunication Network Voltage (TNV) circuits. In the event of high voltages (>TNV) appearing at the external alarm inputs, the Flexible Access Module (variant 25U JJ00 750 HPD) or the External Alarm Module may need to be replaced.

External alarm integrityIt is not possible to guarantee the integrity of the end-to-end transmission link, therefore external alarms are only reported remotely if the transmission link is maintained. The external alarms should not be used for life dependent or hazardous activities.



Performance monitoringThe Nortel TN-1X generates performance monitoring information at various levels of the SDH (performance monitoring points - PMPs). This information is processed by the Subrack Controller and stored as performance logs. These logs are used as the basis for performance monitoring and are accessible from the user interface. Performance monitoring allows the user to measure transmission quality on an on-going basis.

Note: By default, all collection of all performance monitoring data and the monitoring of performance monitoring alarms are disabled.

Types of parity error countsThe TN-1X provides two types of parity error counts, bit counts and block counts:

• Bit counts are the sum of all Bit Interleaved Parity (BIP) parity errors detected in the count period (nominally 1 second).

• Block counts are the sum of all BIP blocks in error detected in the count period (nominally 1 second).

The option to use either bit counts or block counts is configurable on a multiplexer wide basis via the user interface (default is Block counts).

Note: Some PMPs do not support Block counts. If Block counts are selected, PMPs which do not support Block counts will use Bit counts. All performance logs/reports indicate the basis (bit or block) for the displayed counts.

Performance countsThere are a number of performance counts that are accumulated within the TN-1X. These are:

• Errored Seconds (ES). An ES is a second in which at least one anomaly (parity error/code violation) or performance defect (alarm) occurs. The total number of errors is not recorded. See Table 5-2 for list of anomalies and defects.

• Severely Errored Seconds (SES). An SES is a second in which either a threshold level of anomalies is exceeded or a performance defect occurs. The actual number of errors within this second is not recorded. An SES is also, by definition, an ES. The threshold number of errors which distinguish an ES from an SES can be configured by the user, for both bit and block counts.

• Background Block Errors (BBE). A BBE is a block (not included in a SES) in which there is an anomaly.

• Unavailable Seconds (UAS). A UAS is any second which forms part of a period of unavailable time (UAT). A period of UAT starts with the onset of ten consecutive SESs (included in UAT). The period of UAT ends when there are ten consecutive non-SES seconds (not included in the UAT).



5

Note: During periods of UAT, the ES, SES and BBE statistics are not recorded. The start of the UAT is indicated by ten consecutive SES. Until this ten seconds is complete, however, it is unclear whether the ES, SES and BBE figures accumulated will be recorded. As a result, there is a ten second delay in all performance monitoring timestamps.

• Out Of Frame (OOF) seconds. A OOF second is recorded when one or more out-of-frame condition is detected within the regenerator section overhead of an STM-1 frame.

• Pointer Justification Events (PJE). A PJE is recorded when a positive or negative movement of a payload pointer within an STM-1 frame is detected. The bytes that point to the payload will vary depending on the payload. The total number of negative PJEs is also recorded. The difference between these two counts identifies the number of positive pointer movements.

• Assessed Seconds (AS). The AS is the number of seconds during which the performance monitoring statistics were accumulated. Typically, this is equivalent to the length of the performance monitoring period. However, if the TN-1X is rebooted, or the performance monitoring period is terminated early, or the clock changes, the AS total may be shorter or longer than the performance period,

Performance monitoring pointsPerformance monitoring points (PMPs) are points at which performance data is collected. This data relates to the quality of the transmission path passing through that point.

Note: TN-1X hardware only provides monitoring at a traffic termination path. As a result, no performance data that relates to through traffic can be collected.

PMPs and the performance counts they accumulate are listed in Table 5-1.



Performance anomalies and defectsThe basis for determining performance anomalies and defects are detailed in Table 5-2.

Table 5-1Performance monitoring points (PMPs) and error counts

PMP Description ES SES BBE UAS OOF PJE

RS Regenerator Section Yes Yes Yes Yes - -

RS-OOF Regenerator Section Out Of Frame

- - - - Yes -

MS Multiplexer Section Yes Yes Yes Yes - -

HP High-order Path Yes Yes Yes Yes - -

HP-FE High-order Path Far End

Yes Yes Yes Yes - -

AU-PJE Administrative Pointer Justification Events

- - - - - Yes

LP Low-order Path Yes Yes Yes Yes - -

LP-FE Low-order Path Far End

Yes Yes Yes Yes - -

TU-PJE Tributary Unit Pointer Justification Events

- - - - - Yes

PPI-CV PDH Physical Interface Code Violations

Yes Yes Yes Yes - -



5

Table 5-2PMP anomalies and defects

PMP Definition Anomalies Defects

RS B1, BIP-8 B1 Bit Errors RS-LOSRS-LOF

RS-OOF A1, A2 RS-LOF

MS B2, BIP-24 B2 Bit Errors All RS defectsMS-AISMS-EXC

HP B3, BIP-8 B3 Bit/Block Errors(see Note 1)

All RS defectsAll MS defectsAU-AISHP-LOMAU-LOPINT-AU-AISINT-AU-LOP

HP-FE G1, REI G1 Block Errors HP-RDI

AU-PJE(see Note 2)

H1, H2 AU Pointer

LP V5 Bits 1, 2 BIP-2 V5 Bit/Block Errors(see Note 3)

All RS defectsAll MS defectsAll HP defectsTU-AISTU-LOPINT-LP-OP_Buffer

LP-FE V5 Bit 3, REI V5 Block Error HP-RDILP-RDI

TU-PJE(see Note 3)

V1, v2 TU Pointer

PPI-CV HDB3 Code Violations HDB3 CV PPI-LOSPPI-AIS

Note 1: Block error counts are not available on Payload Manager 25U PJ00 750 GXF.Note 2: AU-PJE counts are not available on Payload Manager 25U PJ00 750 GXF or

STM-1 Tributary Units 25U JU00 750 GVA/GVB or 25U TM00 750 HWE.Note 3: Block error or TU-PJE counts are not available on 2 Mbit/s Tributary Units

25U JU00 750 GXG/GXR.



Performance monitoring periodsPerformance monitoring data is accumulated over a performance monitoring period. There are two types of monitoring periods. These are:

• Twenty-four hour (24H) monitoring period. Performance monitoring results can be calculated for any twenty four hour period. The starting hour for such a period can be configured by the user, though the default start time is midnight.

• Fifteen minute (15M) monitoring period. Performance monitoring results are automatically calculated for each fifteen minute period of the day. The start and end times for 15M monitoring periods are fixed.

Both 15M and 24H monitoring periods can be terminated prematurely. In this instance (like scheduled termination), performance results are stored as logs (see Performance logs, below), totals are reset, and a new monitoring period begins immediately. This new period, however, will end at the time when the terminated period was scheduled to end.

The exception to the above rule is when a terminated 15 minute period has less than half of its scheduled fifteen minutes remaining. In this instance, the new period will not end at the scheduled end of the current period, but will continue to the end of the next 15 minute period. As a result, the duration of the new period can be over twenty two minutes.

Performance logsPerformance logs store the results of individual monitoring periods in which monitoring is active. These logs are numbered from ‘1’, with the latest logs having the highest log numbers (entering ‘-1’ as the log number will display the latest log).

The number of performance logs that the TN-1X can store is variable, as it depends upon the number of PMPs that are enabled. A minimum of sixteen 15 minute performance logs can be stored. This is equivalent to 4 hours, assuming no premature terminations are performed. A maximum of two 24 hour logs can be stored.

If it is not possible to store a new performance log, the oldest will be deleted. To avoid loss of data, the EC-1 must upload performance monitoring results frequently.

CAUTION15 minute performance monitoringThe wider range of performance monitoring options provides greater flexibility when monitoring service quality. 24 hour performance monitoring is used for normal performance monitoring measurements. 15 minute performance monitoring produces large quantities of data, and should only be used on a manual basis for specific maintenance measurements. Do NOT use it to collect performance monitoring data automatically.



5

The following performance logs are available:

• 15 minute performance log.

• 24 hour performance log.

• intermediate performance log.

• UAT performance log. This log displays unavailable time information.

Quality of service violation alarmsQuality Of Service Violation (QOSV) alarms are raised on a PMP basis if any of the ES, SES, BBE and UAS parameters exceed user configurable thresholds. These alarms, which can be enabled and disabled on a PMP basis, can only be raised if both monitoring and alarm raising are enabled for the affected PMP. QOSV thresholds can be defined by the user, on both a BIP and block basis.

Note 1: If alarm raising is disabled for a PMP, monitoring is unaffected. Error counts will still be collated, and results will be stored. These results, however, will not be used to trigger alarm events.

Note 2: If monitoring and alarm raising are enabled for a connection and the physical connector is not present, QOSV alarms will be raised for the PMP and will persist until the end of the current monitoring period.

Path trace (J1 byte)The Synchronous Digital Hierarchy provides a path trace capability. For the Nortel TN-1X, the path trace capability allows internal paths to be verified at the VC-4 level.

The VC-4 path overhead bytes contain a path trace byte (J1 byte). The multiplexer cyclically transmits a 16 byte string. The string consists of a frame start marker byte (which contains a CRC-7 calculation over the previous frame) and 15 user configurable bytes. The incoming string is checked against the expected receive string, any discrepancy generates a HP-TIM alarm. The transmit 15 user bytes and the expected receive 15 user bytes are set up via the user interface.

Note 1: When setting the transmit and receive values, all 15 characters of the string must be set otherwise a ‘HP-TIM’ alarm will be raised.

Note 2: Although the user interface allows the user to change the path trace settings for STM-1 Tributary Units 25U JU00 750 GVA/GVB and 25U TM00 750 HWE, the path trace is fixed to the default setting on the unit and cannot be changed. If inter-connecting with an STM-1 Aggregate Unit, ensure the expected receive value for the STM-1 Aggregate Unit is set to the default setting to prevent a ‘HP-TIM’ alarm being raised.

Note 3: The default settings are ‘RX_UNALLOCATED_’ for the receive value and ‘TX_UNALLOCATED_’ for the transmit value.

Note 4: The path trace format used for this release is not compatible with releases 5 and before. As a consequence, a HP-TIM alarm will be raised if the Release 7 TN-1X is connected to an TN-1X Release 5 or earlier.



The system can be configured to generate TU-AIS and HP-RDI consequent actions as a result of a HP-TIM alarm. The consequent actions are enabled/disabled individually via the user interface.

Note: If consequent actions are enabled and the path trace is changed, a caution is given indicating that this action may cause traffic disruption.

Single fibre workingWhen operating in a single fibre mode (i.e. one optical fibre to carry bi-directional optical signals between adjacent multiplexers), if the fibre breaks the transmitted signal may be echoed to the receive optical port on the same multiplexer. This signal must be recognised as faulty and AIS transmitted downstream. The Path Trace facility should be used to ensure signal integrity by setting the transmit and receive path trace settings to different values and enabling consequent actions.

By using the path trace facility with the consequent actions enabled, a HP-TIM alarm will be raised and AIS transmitted downstream if a fibre break occurs and the echoed signal is sufficient to constitute a valid signal.

Note: If HP-RDI is enabled as a consequent action of a HP-TIM alarm, the transmitted signal will be received in the echoed signal and will cause a HP-RDI to be raised on the multiplexer generating it.

Signal label (C2 and V5 bytes)The path overhead provided by the Synchronous Digital Hierarchy includes signal label information which indicates the composition of the signal. For the Nortel TN-1X, signal label information is provided in the VC-12 and VC-4 path overheads.

The VC-12 path overhead contains three signal label bits (bits 5 to 7 of V5 byte), allowing eight different values (‘0’ to ‘7’). The meaning of the eight values is as follows:

• ‘0’ indicates that the VC-12 path is unequipped

• ‘1’ indicates that the VC-12 path is equipped with a non-specific payload

• ‘2’ indicates that the VC-12 path is equipped with asynchronous mapping

• ‘3’ indicates that the VC-12 path is equipped with bit synchronous mapping

• ‘4’ indicates that the VC-12 path is equipped with byte synchronous mapping

• ‘5’ to ‘7’ are reserved to be defined for future specific VC-1 mappings

Any value received other than ‘0’ indicates an equipped VC-1 path. The value is set to ‘0’ automatically if the tributary (VC-12 path) is unequipped. On current equipment, the value should be set to ‘2’ for equipped paths (default).

Note: If the Tx Signal Label is set to ‘0’, the PPI-LOS alarm is disabled. If a valid signal is applied to the appropriate input with the Tx Signal Label set to ‘0’, a PPI-Unexp_Signal alarm will be raised.



5

The VC-4 path overhead contains a signal label byte (C2), allowing 256 different values (‘0’ to ‘255’). A value ‘0’ indicates that the VC-4 path is unequipped. A value ‘1’ indicates that the VC-4 path is equipped with a non-specific payload, a value ‘2’ indicates that the VC-4 path is equipped with a TUG structure. The remaining values (‘3’ to ‘255’) are reserved to be defined for specific VC-4 mappings. Any value received other than ‘0’ indicates an equipped VC-4 path condition. The value ‘0’ should be set if the section is complete but there is no VC-4 path originating equipment and is therefore not used in present applications. On current equipment, the value should be set to ‘2’ (default).

Note: The Tx Signal Label can be set to any value between ‘1’ and ‘255’ and the Rx Signal Label can be set to any value between ‘0’ and ‘255’.

The transmit and receive values are set up via user interface. Any discrepancy between the receive value and the expected receive value generates a signal label (PLM) alarm at the appropriate level (i.e. LP-PLM for VC-12 and HP-PLM for VC-4).

SoftwareAll operational software is stored in non-volatile memory on the Subrack Controller. The Subrack Controller is installed with ‘foundation’ software which includes the operating system and the hardware/software initialisation code. It is possible to download new applications software (for the entire equipment) via the user interface.

Note: Current application software is supplied in compressed format for loading via the CAT and must be decompressed prior to loading.

The Subrack Controller contains Flash memory for two versions of the downloaded application software. The versions held in each bank should be the same at all times except during software upgrades. As only one bank is selected by the TN-1X boot software at any given time, the software in the non-active bank can be upgraded while the other copy is running.

The foundation software selects the bank as follows:

• If a cold (traffic affecting) restart occurs, either at power-up or when the user requests a cold restart, the current bank is used (i.e. the bank is use prior to the restart).

• If a warm (non-traffic) restart occurs, the bank is selected by the user (default is the current bank in use prior to the restart).

A checksum is performed on the selected software, if the test is successful, that software is run. The Subrack Controller contains an automatic reversion facility. If the selected version of the application software fails to start-up successfully, an automatic reversion to the other software bank is carried out. In the unlikely event that both banks fail, the Subrack Controller should be replaced.



The ‘card controller’ on each traffic unit contains non-volatile memory which contains the resident software (i.e. operating system, hardware/software initialisation code and the MMSB communications code) which allows the operating software to be downloaded from the Subrack Controller. Once the traffic unit has performed its power-up sequence, a ‘hard reset’ message is sent to the Subrack Controller (via the control bus), the Subrack Controller then downloads the operating software to the traffic unit. Once the download is complete, a ‘soft reset’ message is sent to the Subrack Controller, which then downloads the configuration data. The operating and configuration data on the traffic units is held in RAM which is checked during the power up sequence (failure of the RAM test results in a Card Fault alarm).

Validation of the operating software on the Subrack Controller and the ‘card controllers’ on the traffic units is periodically performed using checksums. A checksum failure on the Subrack Controller results in an INT-SW_Corrupt alarm. A checksum failure on a traffic unit results in a NE-Card_Fault alarm.

Software upgrade overviewThe software upgrade procedure must start with both software banks containing the same functioning version of the application software. New application software is downloaded into the inactive bank from either the CAT or the TN-MS EC-1. The user is then able to switch to the loaded (new) software in order to test it while retaining the previous software version in the other bank; this permits the user to ‘back out’ to the previous version should the new version prove unsatisfactory.

The TN-1X has two configuration tables, one an active table and the other an inactive table (see “Configuration data” on page 5-19). At the time of a software upgrade, each configuration table becomes associated with a software bank. In this situation, configuration changes made using the new software are not reflected in the configuration table associated with the original software. If the user then reverts to the original software, the changes are lost.

To avoid losing configuration data, the software versions in each software bank should be the same whenever possible. After a short period of testing, if the new software proves satisfactory, the user should commit to the new software (this replaces the old software in the inactive bank with a copy of the new software). The TN-1X is then once more in a stable configuration. If the new software is unsatisfactory, the user should switch to the original old software and backout (this replaces the new software in the inactive bank with a copy of the old software). The upgrade process is shown in Figure 5-2.



5

Software statusThe software status can be checked at all times via the user interface. This should be checked during the software upgrade process as, if the status is not correct for the operation being attempted, then the operation will fail. The software upgrade status can be one of the following:

• StableThe software banks contain the same software version.

• Ready_to_activateThe user has downloaded new software, the latest loaded software version is in the inactive bank.

• Ready_to_commitThe user has downloaded new software, the latest loaded software version is in the active bank.

• Download_in_progressSoftware is being downloaded to the inactive bank.

• Checksum_bankThe download process was aborted, new software must be downloaded or the active software must be copied to the inactive bank.



Figure 5-2Software upgrade overview

Start

New software available

Test new software

SoftwareOK

Yes

No

Backout Commit to new software

Old software in both banks

New software in both banks

Finish

Both software banks contain the original software.

Active Bank contains the original software and Inactive Bank now contains the new software.

If the new software is satisfactory, the user may decide to commit to it. If the new software proves unsatisfactory, then the user must back out, reverting to the original software. In either case, after the software has been tested, the version in each bank should be the same.

While the new software is being tested, the original software can remain in Active Bank. The user may switch between the different software in each bank.

During normal operation, it is important that both banks contain the same software version. If the software in each bank is different, this can interfere with the operation of configuration functions.

Switch to loaded

software

Switch to original

software

Download software to

TN-1X Inactive Bank



5

Configuration dataThe TN-1X has a set of configurable parameters that are required to accommodate various user preferences. The Subrack Controller incorporates two configuration data tables (one active and one inactive), each associated with one software flash bank, and stored in non-volatile memory (battery-backed RAM).

In normal operation, the two configuration tables should contain identical information, one is the operational bank and the other is the backup bank. However, when the application software is being upgraded, each configuration table becomes associated with an application software bank. If the user changes the configuration using the new software, and performs a backout, or commits to new software after changing the configuration using the old software, the recent configuration changes are lost.

The user may backup the current configuration table settings into a file on the CAT or TN-MS EC-1. The configuration data stored in the file may then be restored, which overwrites the data to the inactive table. The user can then make the new configuration data active by switching to the new loaded configuration data. The user is then able to either:

• backout to the old configuration data if necessary (e.g. the new configuration data in incorrect). The old configuration data is then in both tables.

• commit to the new configuration data if the restored data is satisfactory. The restored configuration data is then written to both tables.

The checksum of the non-volatile RAM is periodically checked, failure results in an Internal Configuration Corrupt (INT-NE-Config_Corrupt) alarm.

Changes to the configuration data can be made via either the Element Controller or the CAT. Requests to change configuration data are validated by the Subrack Controller before the configuration data is changed, invalid requests are rejected (e.g. connecting two tributary ports to the same logical channel).

Configuration table statusThe configuration table status can be one of the following:

• StableThe tables are identical, one table is currently active. The status must be stable in normal operating conditions. Other conditions should only be seen when the configuration is being upgraded or restored.

• Ready-to-activateA table has been restored to the inactive bank and has not been activated. The active table holds the current configuration.

• Ready-to-commitA table has been restored and a ‘Switch-to-Restored’ command has been issued, this makes the restored table active.



Detached modeIf the Subrack Controller detects that there is a mismatch between the configuration table and the current traffic configuration, the Subrack Controller enters the Detached mode.

In the Detached mode:

• the Subrack Controller does not control the traffic and the traffic is left running.

Note 1: Manual Payload Manager, N+1 protection, and VC12/VC3 path protection switches are inhibited while the NE is in the Detached mode.

Note 2: While in the Detached mode, ‘NE-Unexpected_Card’ and ‘PPI-Unexp_Signal’ alarms may be raised when cards are present. These alarms will clear once the multiplexer is in the normal operating mode.

• monitoring of the multiplexer is minimal and unreliable.

• an INT-NE-Config_Corrupt alarm is raised.

• the Subrack Controller can still communicate with the Element Controller or CAT.

• the configuration tables can be updated or restored but the changes are not imposed on the traffic cards (non-traffic affecting). When the configuration tables have been updated or restored and are correct, the Impose_Config command can be issued via the user interface which will impose the information in the active configuration table on the traffic cards (possibly traffic affecting).

The Subrack Controller enters the Detached mode in the following circumstances:

• both configuration tables are corrupt or unreadable and there traffic connections.

• the multiplexer is cyclically rebooting and there are traffic connections.

• the Subrack Controller detects a difference between the configuration table and the current traffic configuration.

• the user issues a ‘Default’ command via the user interface. The current configuration table is overwritten with the default settings.

• the NE address on the backplane does not match the NE address held in the configuration table on the Subrack Controller (i.e. the Subrack Controller is in the wrong subrack or a new or replacement Subrack Controller has been inserted). In this situation, an INT-NE-Config_Bp_Mismatch alarm is raised.

To exit from the Detached mode, one of the following user actions is required:

• If the Subrack Controller has been inserted in the wrong subrack, fit the unit in the correct subrack.

• If the Subrack Controller is a new or replacement unit, or is cyclically rebooting, then:

— issue the Default command via the user interface



5

Note: The user must ensure that the correct Payload Managers and Aggregate Units are configured on the NE before imposing defaults. Failure to do so will result in a loss of communications to the NE once the defaults have been imposed. A site visit will be required to correct this situation.

— either Restore a previous configuration table or manually update the current configuration table via the user interface.

— issue the ‘impose_config’ command from the user interface.

• if the multiplexer is not carrying live traffic, perform a cold restart (issue a cold restart command or power cycle off and on).

InventoryThe Subrack Controller maintains an inventory for each unit in the subrack including the Subrack Controller. This inventory includes information, as applicable, about the units fitted (e.g. unit code, card type). The inventory information can be accessed via the user interface.

Local terminal interfaceThe local terminal interface (the ‘F’ interface in the ITU-T SDH recommendations) provides a port capable of supporting a standard intelligent terminal offering full control and monitoring access to the multiplexer or a standard dumb terminal offering read only access to the alarm information (not available on present systems).

Note: When powering-up the TN-1X, ensure that the CAT cable is removed.

For the present systems, the interface uses an IBM-PC compatible ‘Laptop’ computer. The computer must be equipped, as a minimum, with the following features.

For access to Command Line User Interface• 486 processor

• Microsoft Windows™ with Terminal application (emulating a TTY terminal)

• 4 MByte RAM

• 80 Mbyte Hard Disk Drive

• 3.5" 1.44 Mbyte floppy disc drive

• Fully compatible RS-232C serial port

— Data rate: 19200 bit/s

— Word length: 8

— Stop bits: 1

— Parity checking: Not used

— Flow control: hardware



• A printer port

• An externally accessible earth terminal for ESD grounding

For access to Browser User Interface• Pentium 100 processor (or higher)

• Microsoft Windows95 ™

• 16 MByte RAM

• 0.5 Gbyte Hard Disk Drive

• 3.5" 1.44 Mbyte floppy disc drive

• Fully compatible RS-232C serial port

— Data rate: 19200 bit/s

— Word length: 8

— Stop bits: 1

— Parity checking: Not used

— Flow control: hardware

• A printer port

• An externally accessible earth terminal for ESD grounding

Network managementThe Nortel TN-1X is designed to operate in a managed network environment, however, provision is made for the multiplexer to operate in a stand alone mode (using a CAT) where a network management infrastructure does not exist.

The Synchronous Digital Hierarchy includes provision within the section overhead structure for a network management channel, implemented using the International Standards Organisation (ISO) 7 layer Open Systems Interconnect (OSI) reference model.

When operating within a managed network environment, the Nortel TN-1X operates as either:

• A Gateway Network Element (TN-1X only) which communicates with the element controller via a network management interface (Ethernet). The multiplexer also provides network management access to other remote multiplexers via the ‘Embedded Control Channel’ (ECC) within the STM-N frame structure.

• A Network Element (TN-1X and TN-1X/S) which communicates with the element controller, either via a network management interface, or via the ECC and a Gateway Network Element.

The general network management architecture within which the Nortel TN-1X operates is shown in Figure 5-3.



5

Figure 5-3General network management architecture

The various interfaces shown in Figure 5-3 are detailed below:

• Q3 interface. This is the network management interface by which individual multiplexers or subsystems of multiplexers communicate with the next layer of the network management hierarchy (Element Controller). The interface supports an ISO 7 layer OSI interface based on ITU-T recommendations Q.811 (CLNSI) and Q.812. In the physical layer, an Attachment Unit Interface (AUI) is provided compliant with ISO 8802-3. Provision is made via the CAT and Element Controller for enabling/disabling the interface.

Note: The TN-1X/S does not support the Q3 interface.

• ECC interface. This is the ‘Embedded Control Channel’ within the STM-N frame structure which is used for communication between remote multiplexers (i.e. network elements) and the central multiplexers (i.e. gateway network elements). The channel supports an ISO 7 layer OSI protocol based on ITU-T recommendation G.784. In the physical layer, the

GatewayNetworkElement

NetworkElement

GatewayNetworkElement

NetworkElement

Q3 Q3 Q3 Q3

NetworkElement

NetworkElement

NetworkElement Network

Element

NetworkElement

NetworkElement

ECC ECC ECC

Q3ECCECC

Q3

F

LAN

LANQ3

ElementController

Potential StandbyGateway NetworkElement

CentralNode

RemoteNodes

Q3 Network management interfacevia standard LAN (Ethernet)

ECC ‘Embedded Control Channel’within STM-1 frame structure

F Local terminal port

ECC

FF F

F

F

F

F

F

TN-1X/S multiplexers cannot be used in the positions marked



D1 - D3 Data Communication Channel (DCCR) bytes or the D4 - D12 Data Communication Channel (DCCM) bytes are supported, see “Remote Layer Management” on page 5-24.

• F interface. This is a RS232C interface for the CAT. The terminal provides operational/maintenance access to the multiplexer.

Communication on the network management interface and ECC are controlled by the Subrack Controller. Messages received on the network management interface with the local network address are processed. Messages to other addresses are sent via the data communications bus to the appropriate aggregate unit for transmission via the ECC.

Remote Layer ManagementThe TN-1X provides Remote Layer Management which allows limited management of the data communication resources. The Remote Layer Management allows the TN-1X to interwork with other SDH network elements in emerging SDH networks. In particular, Remote Layer Management provides the following capabilities:

• connection of TN-1Xs to STM-1 ports which do not support ECC on higher rate SDH equipment (e.g. TN-16X).

• connection to SDH systems requiring fixed DCC selection.

• stopping management data communications between different operators SDH networks and between incompatible SDH network elements in a SDH network.

The Remote Layer Management provides the following facilities:

• ECC port management. Control of the ECC port, also known as LAPD link, is made via the user interface. If the link is set to Auto, the TN-1X will attempt to establish a connection on the DCCR channel (RS) and then on the DCCM channel (MS) alternately until the link is established. Alternatively, it is possible to force a particular DCC channel to be used via the user interface. Setting RS on, forces the DCCR channel to be used. Setting MS on, forces the DCCM channel to be used.

• LAN port management. Provision is made for enabling/disabling the interface via the user interface.

• Network Layer Address Management supporting Standard Network Layer Address Formats.

CAUTIONManual Area AddressesTake care when changing the Manual Area Addresses, ensure that you are aware of the consequences to communication within your network.



5

TN-1X Network Element

The TN-1X supports the configuration/monitoring of the following Network Layer Addresses:

• NE Network Layer Address

— read/write access to the three Manual Area Addresses for IS-IS area definition.

— read access to the six byte MAC portion (Ethernet). The Ethernet address of the TN-1X is contained in PROM on the subrack backplane. It can only be altered by changing the PROM.

• Network Manager. The Network Manager address is the address which the TN-1X uses for communication with the Element Controller.

— read/write access to the full Network Layer Addresses.

Management System

The TN-MS EC supports the configuration/monitoring of the following Network Layer Addresses:

• TN-MS EC Network Layer Address

— read/write access to the three Manual Area Addresses for IS-IS area definition.

— read access to the six byte MAC portion (Ethernet) MS Network Layer Address, stored on the MS.

• NE Network Layer Addresses

— read/write access to the full Network Layer Addresses (stored on the MS) of the NE within its span of control.

When the TN-1X is added to the Element Controller, the network address is entered on the management system. When the TN-1X is provisioned to bring it under control of the management system, the address is used to set up a communication path with the TN-1X.





Third-party router interoperabilityThe Nortel TN-1X NEs and the TN-MS Element Controller can operate in a network which has multiple routing areas. The Element Controller in a network of multiple routing areas can mange all TN-1X NEs in any or all the routing areas. The Nortel TN-1X NEs and the TN-MS Element Controller can reside in several different Level 1 routing areas and communicate via Level 2 routers.

• Each routing area can include up to 512 End-Systems (ESs) and 150 Intermediate Systems (ISs). The TN-1X NEs are ISs, the TN-MS Element Controller is an ES.

• The network can have at most 20 routing areas.

• The Nortel TN-1X NEs conform to OSI standard ISO 10589 requirements for Level 1 IS-IS routing.

• All nodes (TN-1X NEs and the Element Controller) conform to ISO 9542 requirements for the ES-IS protocol.

end of chapter


6-1

6

Power and synchronisation 6-Power

The Nortel TN-1X and TN-1X/S subracks contain one or two Power Units which provide the +5 V, -5.2 V, +12 V, and -2 V supplies for the subrack units. The Power Units operate in a load sharing mode, however, each Power Unit is capable of supplying the total power requirement. It is possible when in the load sharing mode, to remove or fit one of the Power Units without affecting the performance of the Nortel TN-1X.

The Power Units operate from a battery supply in the range of 40 V to 72 V (nominal 48 V or 60 V).

Each subrack requires two separately fused supplies. The supply to each subrack is normally separately fused. For power supplies of 48 V or 60 V, the fuse rating for each subrack is 7 A.

One supply is used to provide the ‘power’ input to the first Power Unit and the ‘alarm’ input to the second Power Unit. The other supply is used to provide the ‘power’ input to the second Power Unit and the ‘alarm’ input to the first Power Unit. This ensures that power is still available to the subrack if one of the fused supplies fails.

Backplane filtering ensures that plugging any unit into the subrack will not cause a disturbance on the voltage rails sufficient to cause malfunction on any other unit in the subrack.

Each of the derived voltages is monitored and a power supply fail alarm raised if any of the voltages exceed their specified tolerance.

Latest units (25U PW00 750 HSY) are fitted with a front panel On/Off switch.

Power supply to the TN-1X subracks There are normally two independent d.c. station supplies which are connected to fuse holders at the top of the rack.

The remaining information in this sub-section gives a typical power supply arrangement for a ETSI rack fitted with a Rack Alarm Unit.


6-2 Power and synchronisation

The incoming cables are either 10 mm2 or 16 mm2, terminated in a crimped wire pin and sleeved. They are each fixed to the upper of one of the fuse holders which are Klippon type P.O.136H (25S TP00 001 AAA).

For station power supplies of 48 V or 60 V, the fuse rating for each subrack is 7 A. The first fuse position (0) is reserved for the Rack Alarm Unit (if fitted). Its rating is 2 A type, coded 25C PR13 001 GBD.

Up to 10 fuses can be used for the subrack power cables and these are arranged in two groups, each group being connected to one of the independent supplies using link bars to connect adjacent fuses, see Figure 6-1.

The earth cables associated with each subrack supply are connected to the earth tags located at the top of the rack. They then form a twisted pair with the corresponding power cable and pass down the right hand side of the rack.

The power cables to the subracks are 1/1.13 mm2 type. The power cable is coloured blue and the earth cable is black. The twisted pairs are distributed down the rack height so that two twisted pairs are available for use at regular intervals. They are arranged so that the two twisted pairs at regular intervals are from a different group. Since each subrack requires two separate power inputs, these supplies are thus independent. This means that the subracks are protected against a power supply failure.

The power connector is mounted on the Station Service Module and is chosen to suit customer requirements. The backplane has separate earth layers for the 0 V battery input and the signal earths. If required these can be linked by strapping pins on the Station Service Module.

Power supply to the TN-1X/S subracks The power connector is mounted on the Power & LCAP module. The backplane has separate earth layers for the 0 V battery input and the signal earths. If required these can be linked by strapping pins on the Power & LCAP module.


Power and synchronisation 6-3

6

Figure 6-1Typical TN-1X rack power cabling and fusing

IndependentPower SupplyInputs

0 1 2 3 1 2 3

Rack Alarm Unit

Fuse Positions

Network ManagementBus

Cables in the right-hand cable

space

Notes1. The rack has 10 subrack power supply cables. For each of the 10 subrack power cables

there is an associated earth cable. The earth cables are either connected to earth tagsat the top of the rack or to a vertical bar. The live and earth wires form twisted pairs.Groups of 2 twisted pairs are spaced at regular intervals in the rack.

2. In this application only six twisted pairs are used to power three subracks.

3. Indicates that a fuse is fitted Indicates that no fuse is fitted

RackAlarmBusRibbonCable

Subrack 3

Subrack 2

Subrack 1



SynchronisationThe synchronisation source protection functionality of the TN-1X enables the user to control the way in which synchronisation is sourced for the multiplexer. For integration into an SDH network, the TN-1X can synchronise to any external signal traceable to a Primary Reference Clock (PRC).

Synchronisation sourcesThe local clock (155,520 kHz) used for synchronising the TN-1X is provided by the main (active) Payload Manager. For the TN-1X, the synchronising clock can be slaved from any of the following sources:

• Tributary Synchronisation (TS) backplane signal. This signal may be derived from:

— either of the incoming aggregate STM-1 or STM-4 signals, A or B.

— any 2048 kbit/s tributary input

— any STM-1 tributary signal.

Note: If a STM-4 aggregate signal is selected, the signal is derived from the AUG (STM-1) signal being dropped, which is synchronised to the incoming STM-4 signal.

• External 2.048 MHz interface (not available on the TN-1X/S). Connection is via the Star Card module.

• Internal 16.384 MHz master oscillator (with an accuracy of ±4.6 ppm) on the Payload Manager.

Figure 6-2 shows the functionality of the synchronisation source facility.

Figure 6-2Synchronisation source - block diagram

ActivityDetector

ActivityDetector

ActivityDetector

SwitchInternalOscillator

ExternalSync Line

TribSync Line

ActivityDetector

PLL

2M TribUnit

STM-1 TribUnit

AggrUnit

Payload Manager

LocalTiming

ExternalSyncOutput



6

Note 1: Loss of the active synchronisation source can cause loss of all traffic for approximately 200 ms.

Note 2: If a traffic unit provides the current synchronisation source, switch to an alternative synchronisation source before replacing the unit or re-provisioning the multiplexer.

Note 3: Systems with subracks using STM-4 aggregates should not be run with the synchronisation independently set to ‘Internal’. They should be synchronised via the line back to a common source (e.g. a Head Mux set to ‘External’ or ‘Internal’).

Note 4: Do not apply a ‘Local’ loopback for a tributary selected as the active synchronisation source, otherwise the multiplexer will lose synchronisation.

Synchronisation source hierarchyThe basis for synchronisation source protection is the synchronisation source hierarchy. This is formed from four sources identified by the user. The first source has the highest priority for the user, with the fourth having the lowest. A standby signal is also available, which is always the internal oscillator on the Payload Manager. Only sources listed within this hierarchy are considered for use.

The selected synchronisation source is used until the source fails, or a decision to change sources is taken (see “Synchronisation switching mechanisms” on page 6-6 for details).

Synchronisation settingsThe use of the synchronisation source hierarchy is controlled by reversion and force settings as described in the following sections:

Reversion on/offReversion controls the selection of a source if a source fails:

• Reversion on. If a source fails, or a decision to change sources is made, both higher and lower priority sources can be selected for use. The higher priority source is only considered if that source has recovered.

• Reversion off. When a source fails, or a decision to change sources is made, only sources of a lower priority can be selected for use.

If a source fails, a non-reversion flag is set on this source to prevent its re-selection at a later stage. This flag must be cleared manually by the user before that source is available for selection again.

Note: Reversion settings are not used when a source is in forced use (i.e. force on).

Force on/offForce on/off allows the user to manually select the source to be used.

• Force on. Using this setting, one of the sources in the hierarchy, including one that is currently invalid, is selected for use. The TN-1X is not able to change to a different source while in this mode.



If a source becomes invalid while in this mode, or if an invalid source is selected for use, the TN-1X begins a ‘holdover period’. During this period, the TN-1X reproduces the absent synchronisation signal internally. This situation is resolved in either of the following ways:

— If the source becomes stable again during this time, the source is used as if had not been interrupted.

— If the holdover period ends (typically after five seconds) without the source becoming available, the standby source (the internal oscillator) is used.

Note 1: When a source is in forced use, reversion settings are ignored.

Note 2: During holdover, a QL =15 is transmitted for Payload Manager variant 25U PJ00 750 GXF and QL = 11 is transmitted for Payload Manager variants 25U PJ00 750 HZQ and NTKD10AA.

• Force off. Using this setting cancels any existing forced source usage, and source selection comes under the control of reversion setting. Existing non-reversion flags are unaffected when this mode is selected.

Note: The circumstances under which a switch in synchronisation occurs depends on the implementation mechanism used.

Synchronisation switching mechanismsThe circumstances under which a switch in synchronisation occurs depends on the implementation mechanism used. There are two mechanisms:

• A Synchronisation Status Messaging (SSM) mechanism. This uses transmitted quality levels to determine the best source. See “Synchronisation status messaging” on page 6-6.

• A non-SSM system. This is similar to the synchronisation mechanism used by the TN-1X before Release 7. See “Non-SSM synchronisation sourcing” on page 6-12.

Note: Both of these mechanisms make use of the software settings described in “Synchronisation settings” on page 6-5.

Synchronisation status messagingSynchronisation status messaging (SSM) is based on the transmission of synchronisation quality messages between potential synchronisation sources. Using this system, the TN-1X is able to evaluate which synchronisation source is the best for use. This evaluation is used under two circumstances:

• The best source will always be selected for use, subject to software settings restrictions (see “Synchronisation settings” on page 6-5). That is, if a better quality source is identified (and no source is in forced use), the current reversion settings will dictate whether this source can be selected for use.

• In the event of a source failure, the best of the remaining sources will be selected for use, subject to software settings restrictions (see “Synchronisation settings” on page 6-5). If no source is available, the standby source is selected.



6

Note: The SSM mechanism can only select sources that are listed in the synchronisation source hierarchy.

The Quality Level (QL) of a source is transmitted in the section overhead of all STM-N signals as the S1 byte. QL has a possible range of 1 to 15, with 1 as the highest priority. In practice, a subset of these values is used by the TN-1X. This subset of QL values is defined in Table 6-1.

The TN-1X transmits its QL on all STM-N ports, except for the STM-N port from which it receives its synchronisation source. The QL transmitted on this port is 15, which indicates to the source of the synchronisation that the TN-1X should not be used for synchronisation. This action prevents closed synchronisation loops, where two multiplexers each attempt to synchronise from the synchronisation signal of the other.

By default, each TN-1X uses its internal clock, which has a QL of 11.

The user can configure the QL settings for both RX and TX purposes. These manual settings override any QL values established by the TN-1X software.

Note: Early Aggregate Units are unable to receive or transmit QL values. The QL for these aggregates will default to 15 (“do not use for sync”).

Table 6-1QL settings for use with SSM

QL Meaning Description

0 Synchronisation quality unknown.

Included for backwards compatibility reasons. Will always be interpreted by multiplexer as QL = 15.

2 Traceable to Primary Reference Clock (PRC).

The external timing source for the network.

4 Traceable to Transit Clock. A clock provided for equipment which does not connect with customer equipment. That is, it only connects to other nodes.

8 Traceable to Local Clock. A clock provided for equipment which connects directly with customer equipment.

11 Traceable to SDH Equipment Clock (SEC).

The internal oscillator of the multiplexer.Note: This is the default setting.

15 Do not use for synchronisation.

This is prevents the multiplexer’s synchronisation source from being used by multiplexers that receive this value.



Synchronisation status messaging network examplesSimple ring with a single reference sourceAn example simple ring network with a single reference source is shown in Figure 6-3.

Figure 6-3SSM within a simple STM-N ring with a single external source

In the example of Figure 6-3, synchronisation is derived from the Primary Reference Clock (PRC). The PRC is the external (EXT) source with a QL=2 at TN-1X(A). The other TN-1Xs in the ring have their hierarchy set to derive synchronisation from the counter-clockwise TN-1X in preference to the clockwise TN-1X (i.e. on their B ports in preference to A). The QL = 2 clock is transmitted on all STM-N ports for the TN-1X, with the exception of the return port of the synchronisation source, on which QL = 15 (“do not use for synchronisation”) is transmitted. This prevents closed synchronisation loops.

Note: Before the PRC signal was introduced, all four TN-1Xs would have used the default QL setting of 11, which indicates the use of an internal oscillator (INT).

If a fibre break occurs, the TN-1Xs after the break will send a QL = 11 in the counter-clockwise direction. The last TN-1X in the ring will switch to the higher quality clock (QL = 2) being sent from the TN-1X with the PRC in the clockwise direction. The QL = 2 clock is then available from its clockwise port, so moving in a clockwise direction around the ring each TN-1X will switch to the PRC QL = 2 clock. The ring will then be synchronised to the highest available quality clock.

QL = 2

QL = 2TN-1X (A)

PRC

2

2

15

15

STM-N RING

(An EXTernal source)

Hierarchy=EXT

QL = 2TN-1X

Hierarchy=B, AQL = 2TN-1X

Hierarchy=B, A

QL = 2TN-1X

Hierarchy=B, A

2

15

2

2

A B

A

B

AB

A

B



6

Simple ring with two reference sourcesAn example simple ring network with a two reference sources is shown in Figure 6-4.

Figure 6-4SSM within a simple STM-N ring with two external sources

Synchronisation is derived from the Primary Reference Clock (PRC). The PRC is the external (EXT) source with a QL=2 at TN-1X(A). There is also a Secondary Reference Source (SRC) which is also external and has a QL = 3 at TN-1X(B). The other TN-1Xs in the ring have their hierarchy set to derive synchronisation from the counter-clockwise TN-1X in preference to the clockwise TN-1X, i.e. on their B ports in preference to A. The QL = 2 clock is transmitted on all STM-N ports for the TN-1X, with the exception of the return port of the synchronisation source, on which QL = 15 (‘do not use for synchronisation’) is transmitted. This prevents closed synchronisation loops.

In the event of a failure of the primary reference source the TN-1X with the primary source switches to an internal clock with a QL = 11. This will propagate around the network until it reaches the TN-1X with the secondary reference source which will switch to the SRC and transmit a QL = 3. This will then propagate around the network in a clockwise direction with the other TN-1Xs synchronising to the secondary reference source.

Note: The hierarchy on the TN-1Xs with the external sources are set so that one synchronises in a clockwise direction around the ring and the other in a counter-clockwise direction. This is to prevent synchronisation timing loops.

QL = 2

QL = 2TN-1X(A)

PRC

2

2

15

15

STM-N RING

(An EXTernal source)

Hierarchy=EXT, B

QL = 2TN-1X


Hierarchy=B, A

QL = 2TN-1X(B)

Hierarchy=EXT, B

2

15

2

2

QL = 3SRC (An EXTernal source)

A B

A

B

AB

A

B



Chain network with two reference sourcesAn example simple chain network with a two reference sources is shown in Figure 6-4.

Figure 6-5SSM within a simple STM-N ring with two external sources

For a chain network, there must be two reference sources, one at each end of the network. In normal operation, the chain will derive its synchronisation from the primary source. In the event of failure of the primary reference source, the chain will derive its synchronisation from the secondary reference source. In the event of a loss of a link, the chain will divide into two synchronisation islands, one using the primary reference source and the other the secondary reference source.

Inter-operating with non-SSM networksAn example simple ring network inter-operating with a non-SSM network is shown in Figure 6-4.

In this example, the TN-1X ring is subtended to a non-SSM TN-16X ring via an STM-1 tributary. In this situation, it is necessary to override the receive and transmit QL settings on the STM-1 tributary at the TN-1X inter-connecting with the TN-16X ring.

In the example, the rx override on the STM-1 tributary at TN-1X(A) is set to a value of 4 (the value should correspond to the value of the synchronisation source in the TN-16X ring). This value is transmitted around the TN-1X and is used as the synchronisation source (assuming no higher level source is available).

Note: The rx override can be configured to a value between 1 and 15. Setting the rx override to a value between 11 and 15 will cause the TN-1Xs to run from their internal source.

It is recommended that the tx override of the STM-1 tributary is set to a value of 15 (do not use). This provides an additional safeguard if the non-SSM equipment becomes SSM compatible.

QL = 2

QL = 2TN-1X

PRC

2

15 15

2

15

2

QL = 3SRC

QL = 2TN-1X

QL = 2TN-1X

QL = 2TN-1X



6

Note: If the TN-16X ring is not the source of synchronisation for the TN-1X ring, the rx and tx overrides for the TN-1X STM-1 tributary should be set to 15 (do not use) or the STM-1 tributary removed from the synchronisation hierarchy.

Figure 6-6SSM within a simple STM-N ring inter-connecting with non-SSM network

SSM recommendationsSSM can be used to increase the resilience of the synchronisation network to network faults such as fibre breaks. It can also be used where the network is carrying synchronisation sensitive services such as video.

SSM simplifies some operational aspects of synchronisation design, however, care must be taken to avoid timing loops during the transition to SSM. The following are recommendations regarding SSM:

1 If upgrading from an earlier TN-1X release where the synchronisation is operating correctly, do not use SSM.

2 If SSM is to be deployed:

a. Have a clear understanding of how you wish to configure SSM to operate in your network.

b. Develop a detailed plan for the configuration.

c. Set up the quality levels and priorities on each NE in the network first.

QL = 4TN-1X

4

4

15

15

STM-N RING

Hierarchy=B, A

QL = 4TN-1X


Hierarchy=B, A

QL = 4TN-1X(A)

Hierarchy=C

4

4

4

15

A B

A

B

A

B

A

B

TN-16X

A

B

C

TN-16X Ring (non-SSM)

TN-1X Ring (SSM)

Rx override=4 Tx override=15



d. Initiate SSM on the NE from which the synchronisation source is derived.

e. Initiate SSM on the next NE in the network.

f. Continue working around the network initiating SSM on each NE in turn.

3 Avoid timing loops:

— During SSM configuration, ensure that there are no NEs without SSM initiated between NEs that have SSM initiated.

— If some NEs do not support SSM, SSM should not be used in that ring or chain.

— Do not mix SSM on a port, i.e. a port should have both or neither rx override and tx override set to SSM.

— If rx override and tx override are not set to SSM, at least one must be set to a QL = 15, i.e. a fixed configured port may use a received synchronisation or transmit a usable synchronisation, but not both.

— Normally a STM tributary port should only be set to a fixed QL, i.e. non-SSM, because either the other end of the link does not support SSM or it is required not to use SSM over that link. This is the case at a network boundary, e.g. span of control limit, operator boundary, inter-link between rings.

4 When an NE uses its Internal synchronisation source as the reference source, it is recommended that the rx and tx override values for the aggregates of that NE are configured to a value of less than 11. This is because the non-configurable Internal source has an QL = 11, which is the same as the holdover QL value (for a digital PLL).

5 If a single NE brings the synchronisation into the network, do not have the aggregates in the synchronisation hierarchy at that NE. This avoids the situation where the aggregates receive a QL which is higher than all others and is consequently selected as the NE QL. In this situation, all NEs would be synchronised off aggregates, resulting in ‘timing loops’ and loss of the external reference source. To resolve this, the synchronisation hierarchy would need to be re-applied.

Non-SSM synchronisation sourcingWhen the SSM system is not in use, changes to the selected synchronisation source only occur when a source fails, or if a manual change is performed. Changes due to source failure as subject to software settings restrictions (see “Synchronisation settings” on page 6-5). With SSM off, the TN-1X can operate in one of three modes dependent on the reversion and force settings (these modes are similar to the synchronisation schemes used prior to Release 7):

• Manual-only selection mode (MANUAL). In this mode automatic selection of the synchronisation source is disabled. The synchronisation source is selected manually by the user. The user can select any available



6

synchronisation source, no validity check is provided on the selected source. This mode is selected by setting force on and SSM off (the reversion setting has no effect).

• Automatic switching with manual reversion mode (FALLBACK). In this mode the multiplexer switches to the next highest priority valid source if the selected synchronisation source fails. If a higher priority synchronisation source recovers, it is not automatically selected as the synchronisation source. To switch back to the higher priority source, the user must perform a manual reversion. This mode is selected by setting reversion off, force off and SSM off.

• Automatic switching with automatic reversion mode (REVERSION). In this mode the multiplexer switches to the highest priority valid source available. If a higher priority synchronisation source recovers, the source is automatically selected as the synchronisation source. This mode is selected by setting reversion on, force off and SSM off.

Failure of synchronisation sourceWhen automatic switching is selected (either with manual reversion or automatic reversion), the validity of the source is checked prior to switching. The following alarms and activity detectors are used to determine the validity of the source:

• STM-1 and STM-4 aggregate ports, STM-1 tributary ports

— RS-LOS

— RS-LOF

— MS-AIS or AU-AIS

— MS-EXC

• 2048 kbit/s tributary ports

— PPI-LOS

— PPI-AIS

— PPI-EXC

• Tributary Synchronisation Activity Detector

• External Sync Source Activity Detector

• Internal Oscillator Activity Detector

• SETG Fail alarm

Failure hold-off timeIf a synchronisation source fails, a check is performed to check that it has failed continually for a period of time. The period of time, known as the “failure hold-off time”, is configurable via the user interface.

Wait to restore timeWhen a synchronisation source recovers, a check is performed to check that it has recovered for a period of time. The period of time, known as the “wait to restore time” is configurable via the user interface.



External synchronisation outputThe Nortel TN-1X provides an external 2048 kHz synchronisation output signal (via the Star Card module) in accordance with ITU-T recommendation G.703, the output signal is present at all times.

Synchronisation alarmsThere are five alarms associated with the synchronisation facility, namely:

• ‘SYNC-SETG_Fail’ - indicates failure of the currently selected source.

• ‘SYNC-Src_Not_Primary’ - indicates that the primary synchronisation source is not currently selected.

• ‘INT-SYNC-Trib_Line_Fail’ - indicates that the status of the Trib Sync line is unreliable (i.e. activity is detected when not expected or no activity when expected). The alarm is detected during a synchronisation source switch and indicates that either the unit that was providing the source has not switched it off, or the unit providing the new synchronisation source has not switched it on.

• ‘INT-SYNC-Oscillator_Fail’ - indicates that the internal oscillator has failed.

• ‘SYNC-Ext_ Sync_LOS’ - indicates that the external synchronisation source has failed.

end of chapter


7-1

7

System parameters 7-This chapter provides the performance specifications for the TN-1X and TN-1X/S multiplexers.

Operating parametersPower requirements

Input supplyTwo independent separately fused d.c. supplies (per subrack) in the range 40 V to 72 V, positive earth. A 7 A fuse should be fitted to each supply.

Power consumptionTypical power consumptions for each of the units are listed below:

Subrack Controller: 11.0 WPayload Manager: 10.3 W2 Mbit/s Tributary Unit: 8.2 W34 Mbit/s Tributary Unit: 8.05 WSTM-1 Optical Aggregate Unit: 7.9 WSTM-1 Electrical Aggregate Unit: 10.1 WSTM-4 Optical Aggregate Unit: 21.9 WSTM-1 Optical Tributary Unit (2”): 10.9 WSTM-1 Optical Tributary Unit (1”): 8.0 WSTM-1 Electrical Tributary Unit: 12.9 WEOW Unit: 8.0 W

The efficiency of the Power Units is greater than 75%.

ConstructionEquipment practiceExternal dimensions conform to draft ETSI standard pr ETS 300-119 part 4.

Nortel TN-1X subrack (shelf)Height: 525 mm, 21 Standard Unit (SU)

where a SU is equivalent to 25 mm. Width: 450 mm

535 mm including flangesDepth: 250 mm (without plug-in units)


7-2 System parameters

Nortel TN-1X/S subrackHeight: 325 mm, 13 SU Width: 450 mm

535 mm including flangesDepth: 250 mm (without plug-in units)

Plug-in unit aperture dimensionsHeight: 266.7 mmWidth: 426.72 mm, 84 pitches of 5.08 mm

Cable interface area dimensionsHeight: 266.7 mm (TN-1X)

50 mm (TN-1X/S)Width: 426.72 mm

Plug-in unitsHeight: 233 mm (excluding ejectors levers)Depth: 220 mm (excluding connectors and front panel)Widths: n x 5.05 mm, where n = 5, 8, 9 or 10.

Interface modules• TN-1X

• Height: 250 mm (excluding ejectors levers)Depth: 55 mm (excluding connectors and front panel)Widths: n x 5.05 mm, where n = 5 or 8.

• TN-1X/S

— Traffic interface modules

• Height: 25.5 mmDepth: 55 mm (excluding connectors and front panel)Width: 250 mm (excluding ejectors levers)

— Station interface modules

• Height: 25.5 mmDepth: 55 mm (excluding connectors and front panel)Width: 160 mm (excluding ejectors levers)

Weight• TN-1X subrack

Unequipped subrack: 8 kgFully equipped Nortel TN-1X subrack: 20 kg (maximum).

• TN-1X/S subrackUnequipped subrack: 9.5 kgFully equipped Nortel TN-1X/S subrack: 18 kg (maximum).


System parameters 7-3

7

System interfacesMost external system interfaces are made via Interface Modules in the Station Interface Area of the TN-1X subrack or via Connector Panels in the Station Interface Area of the TN-1X/S subrack. Different Interface Module and Connector Panel types are available to cater for specific customer connector requirements.

Optical interfaces are made via optical connectors on the front of the optical units.

The Local Craft Access Panel (LCAP) on the TN-1X and the EOW/CATT Connector Panel on the TN-1X/S provide interfaces for frequently used features (e.g. local terminal).

2048 kbit/s traffic2 Mbit/s tributary inputs and outputs interfaces conform to ITU-T recommendation G.703 as follows:

Line rate: 2048 kbit/s ± 50 ppmLine code: High Density Bipolar 3 (HDB3)Access impedance: 75 Ω or 120 ΩOutput pulse height: ±2.37 V ± 10% (75 Ω) peak

±3 V ± 10% (120 Ω) peakNominal pulse width: 244 nsCable loss to input: 0 dB to 6 dB at 1024 kHz,

typically maximum of 330 m of 2002 cabletypically maximum of 470 m of 2003 cabletypically maximum of 280 m of 3002 cable

Input return loss: not less than 12 dB in the range50 kHz to 100 kHznot less than 18 dB in the range100 kHz to 2048 kHznot less than 14 dB in the range2048 kHz to 3072 kHz

Output return loss: not less than 6 dB in the range512 kHz to 1024 kHznot less than 8 dB in the range1024 kHz to 3072 kHz.

34368 kbit/s traffic34 Mbit/s tributary inputs and outputs interfaces conform to ITU-T recommendation G.703 as follows:

Line rate: 34368 kbit/s ± 20 ppmLine code: High Density Bipolar 3 (HDB3)Access impedance: 75 ΩOutput pulse height: 1.0 V ± 0.1 V peakNominal pulse width: 244 nsCable loss to input: 0 dB to 12 dB at 17184 kHz,

typically maximum of 250 m of 2003 cable



Input return loss: not less than 12 dB in the range860 kHz to 1720 kHznot less than 18 dB in the range1720 kHz to 34368 kHznot less than 14 dB in the range34368 kHz to 51550 kHz

Output return loss: not less than 6 dB in the range859.2 kHz to 1718.4 kHznot less than 8 dB in the range1718.4 kHz to 51552 kHz.

STM-1 optical - long haulThe STM-1 long haul aggregate/tributary optical inputs and outputs exceed ITU-T recommendation G.957 (application code L-1.1) for 155,520 kbit/s STM-1 signals. The optical interface is as follows:

Output power: maximum 0 dBmminimum –5 dBmnominal –2.5 dBm

Receiver sensitivity: –35.5 dBm (error rate 1 in 1010)Receiver overload: 0 dBmOptical path penalty: 1 dBSection loss: 0 dB to 29.5 dB (TN-1X to TN-1X)Wavelength (nominal): 1310 nmSpectral range: 1285 nm to 1330 nmFibre type: monomode.

STM-1 optical - short haulThe STM-1 short haul aggregate/tributary optical inputs and outputs exceed ITU-T recommendation G.957 (application code S-1.1) for 155,520 kbit/s STM-1 signals. The optical interface is as follows:

Output power: maximum –8 dBmminimum –13.5 dBmnominal -10 dBm

Receiver sensitivity: –34.5 dBm (error rate 1 in 1010)Receiver overload: 0 dBmOptical path penalty: 1 dBSection loss: 0 dB to 20 dB (TN-1X to TN-1X)Wavelength (nominal): 1310 nmSpectral range: 1280 nm to 1335 nmFibre type: monomode.



7

STM-1 electrical The STM-1 aggregate/tributary electrical inputs and outputs conform to ITU-T recommendation G.703 for 155,520 kbit/s STM-1 signals. The electrical interface is as follows:

Line code: Coded Mark Inversion (CMI)Access impedance: 75 ΩInput and OutputReturn Loss: not less than 15 dB in the range

8 MHz to 240 MHzCable loss to input: 0 dB to 12.7 dB at 78 MHz

(maximum of 120 m of 2003 cable)Output pulse height: 1.0 V ± 0.1 V peak.

STM-4 optical aggregate - long haul 1310 nmThe STM-4 long haul aggregate optical inputs and outputs exceed ITU-T recommendation G.957 (application code L-4.1) for 622,080 kbit/s STM-4 signals. The optical interface is as follows:

Output power: maximum +2 dBmminimum –3 dBmnominal -0.5 dBm

Receiver sensitivity: –32.5 dBm (error rate 1 in 1010)Receiver overload: –6 dBmOptical path penalty: 1 dBSection loss: 8 dB to 28.5 dB (TN-1X to TN-1X)Wavelength (nominal): 1310 nmSpectral range: 1298 nm to 1323 nmFibre type: monomode.

STM-4 optical aggregate - intra-office 1310 nmThe STM-4 intra-office aggregate optical inputs and outputs exceed ITU-T recommendation G.957 (application code I-4) for 622,080 kbit/s STM-4 signals. The optical interface is as follows:

Output power: maximum –8 dBmminimum –14 dBmnominal –11 dBm

Receiver sensitivity: –27 dBm (error rate 1 in 1010)Receiver overload: –5 dBmOptical path penalty: 1 dBSection loss: 0 dB to 12.5 dB (TN-1X to TN-1X)Wavelength (nominal): 1310 nmSpectral range: 1200 nm to 1348 nmFibre type: monomode.



STM-4 optical aggregate - long haul 1550 nmThe STM-4 long haul 1550 nm aggregate optical inputs and outputs exceed ITU-T recommendation G.957 (application code L-4.2) for 622,080 kbit/s STM-4 1550 nm signals. The optical interface is as follows:

Output power: maximum +2 dBmminimum –3 dBmnominal -0.5 dBm

Receiver sensitivity: –34 dBm (error rate 1 in 1010)Receiver overload: –6 dBmSection loss: 8 dB to 30 dB (TN-1X to TN-1X)Optical path penalty: 1 dBWavelength (nominal): 1550 nmSpectral range: 1540 nm to 1560 nmFibre type: monomode.

Rack alarm busThe rack alarm bus interface (not applicable to the TN-1X/S) provides a connection to the standard 10-way ribbon interface for connection, if applicable, to the Rack Alarm Unit (RAU) at the top of the rack.

Local terminalThe local terminal port is an RS232C asynchronous interface working at 19.2 kbit/s. Connection is via a 25-way D-type connector on the Local Craft Access Panel (TN-1X) or the EOW/CATT Connector Panel (TN-1X/S).

Network managementThe network management port (not applicable to the TN-1X/S) is an Ethernet Local Area Network (LAN) Open Systems Interconnect (OSI) model conforming to ISO 8802.3 with Carrier Sense Multiple Access with Collision Detection (CSMA/CD). The physical interface is an Attachment Unit Interface (AUI) for connection with a LAN transceiver mounted in the same rack.

Provision is made for communication with remote multiplexers via the Embedded Control Channel (ECC) within the STM-1 frame (bytes D1 to D3 or D4 to D12 in the section overhead).

External synchronisation input and outputThe synchronisation inputs and outputs conform to ITU-T recommendation G.703 for 2048 kHz clock signals. No synchronisation inputs or outputs are provided on the TN-1X/S.

External alarmsFive closed contact inputs (i.e. floating inputs with no earth provided) with following characteristics:

Open circuit condition: Greater than 1 MΩ (Normal active alarm state)Short circuit condition: Less than 200 Ω (Normal non-active alarm state)Electrical protection: Alarm inputs protected against accidental

connection to a supply battery with a steadystate voltage up to 72 V.



7

Engineering Order Wire (EOW)The EOW system uses the E1 or E2 Orderwire bytes in the STM section overhead. All TN-1Xs on a ring or line system must be equipped with an EOW Unit.

Maximum number of nodes: 99Facilities: point-to-point calls

broadcast ringingconference call (maximum of 4 partieson a conference call)

Signalling: DTMFTelephone socket: Type 603A socket

ElectroMagnetic compatibilityThe subrack is designed to meet the Class B requirements of European Standard EN 55022.

Environmental conditionsThe subrack is designed to meet the requirements of draft ETSI standard pr ETS 300-019 as follows:

Storage: Class 1.2Transport: Class 2.3Operation: Class 3.1E.

end of chapter


8-1

8

External interfaces 8-Introduction

External connections to the TN-1X subrack are made via the Local Craft Access Panel (frequently used connections) or Interface Modules in the Station Interface Area (SIA) of the subrack.

External connections to the TN-1X/S subrack are made via the Connector Panels, which are in turn connected to the backplane via Interface Modules in the SIA of the subrack.

The following sections provide details of the available LCAPs, Interface Modules, and Connector Panels.

WARNING

Take care when working with cables near the top of the Station Interface Area that your hands do not scrape on the honeycomb screen. Use of a suitable cable extraction/insertion tool is recommended.


8-2 External interfaces

Local Craft Access Panel 75 Ω

The Local Craft Access Panel 75 Ω provides a 25-way ‘D’ type connector for the local terminal, two 75 Ω monitoring points (for future use), and a EOW telephone socket for the TN-1X. The connectors are mounted behind a hinged cover on the left-hand side of the panel (see Figure 8-1).

Figure 8-1Local Craft Access Panel 75 Ω - front view

The local terminal port is a female 25-way ‘D’ type connector. The pin-out of the connector is detailed in Table 8-1.

Table 8-1Local Craft Access Panel 75 Ω - local terminal connector pin-out

Pin Function Pin Function

12345678910111213

Frame ground (0 V)Transmit data (TXD)Receive data (RXD)Ready to send (RTS)Clear to send (CTS)Data set ready (DSR)Signal ground (0 V)No connection+5 V (not used)Detect terminalNo connectionNo connectionNo connection

141516171819202122232425

No connectionNo connectionNo connectionNo connectionNo connectionNo connectionData transmit ready (DTR)No connectionNo connectionNo connectionNo connectionNo connection

RECEIVE ATTALM ACKALARM ESD

TRAFFICMONITORCATT

1

For future use

RECEIVE ATTALM ACKALARM

ESD

Behind hinged cover

EOW

2

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

2425


External interfaces 8-3

8

The subrack alarm facilities are provided by a receive attention push-button switch (‘RECEIVE ATT’), and two LEDs (red ‘ALARM’, green ‘ALM ACK’). These facilities are controlled by the Subrack Controller.

Mating connectors/cablingThe local terminal port (CATT) is an RS232C interface using a 25-way ‘D’ Type socket. The cable must be terminated at the TN-1X end with plug type 32C CN36 100 AKU and 4.40 UNC screws. The cable and connector to the local terminal will depend on which type of local terminal device is used and is therefore customer specific. Cableform 25Y CN00 748 AAA provides suitable cabling and connectors when using a local terminal fitted with a 9-way ‘D’ type connector.

A CW1311 type phone jack socket (EOW) is provided for connection of the DTMF handset for Engineering Order Wire operation.

Two type 43 female coaxial connectors are provided for future traffic monitoring facilities.

The Local Craft Access Panel 75 Ω interfaces to the Flexible Access Module using a cable with 25-way ‘D’ type connectors (cableform 25Y CN00 021 AAA, which is part of the LCAP assembly). The connector body and cable shield are d.c. coupled to the mechanical earth.



75 Ω Traffic Access Module (TN-1X)

The 75 Ω Traffic Access Module (TN-1X), see Figure 8-2, provides sixteen type 43 coaxial connectors for eight 2048 kbit/s tributary ports (a port being a transmit/receive pair) for the TN-1X.

Figure 8-275 Ω Traffic Access Module (TN-1X) - front and side views

LK1

LK2

LK3

LK4

LK5

LK6

LK7

LK8

RX

75 Ω

TR

AF

FIC

AC

CE

SS

MO

DU

LE10

98

76

45

32

125

UJJ

0075

0GV

Z

TX

1

AC Coupled

DC Coupled

2

AC3

DC

1

2

AC3

DC

Link



8

The upper eight connectors (RX) provide the receive (input) connections. Links LK1 to LK8 on the module (see Figure 8-2) allow the coaxial cable shield of each input to be a.c. coupled (pins 2-3 linked) or d.c. coupled (pins 1-2 linked) to the electrical earth. Figure 8-3 shows the relationship between links and the 2048 kbit/s input ports. The lower eight connectors (TX) provide the transmit (output) connections. The coaxial cable shield of each output connector is d.c. coupled to the electrical earth.

The 75 Ω Traffic Access Module (TN-1X) fits into Interface Module positions T2, T3, T5, T6, T10, T11, T13, and T14 (backplane slot positions 10, 15, 25, 30, 50, 55, 65, and 70) in the SIA of the subrack. Two modules are required to provide all the necessary connectors for a 2 Mbit/s Tributary Unit.

The relationship between the 2048 kbit/s ports, the connectors on the 75 Ω Traffic Access Module (TN-1X), and the 2 Mbit/s Tributary Units is shown in Figure 8-3.

Note 1: The input earth links are applicable to the upper receive connectors only.

Note 2: A 75 Ω Tributary Unit must be fitted in the corresponding plug-in unit position if 75 Ω Traffic Access Modules are used (e.g. a 75 Ω Tributary Unit must be fitted in plug-in unit position S2 if 75 Ω Traffic Access Modules (TN-1X) are fitted in position T2 and T3).

Figure 8-375 Ω Traffic Access Module (TN-1X) - 2 Mbit/s port allocation

Mating connectors/cablingThe 75 Ω 2048 kbit/s tributary interfaces use coaxial cables terminated with Type 43 coaxial sockets, the mating connector is coded 32C CN15 001 AAL. The preferred coaxial cable type is 3002, however, type 2002 can also be used.

Port 8

Port 7

Port 6

Port 5

Port 4

Port 3

Port 2

Port 1

Port 16

Port 15

Port 14

Port 13

Port 12

Port 11

Port 10

Port 9

Interface Moduleposition

T2(10)

T3(15)

T6(30)

T5(25)

T10(50)

T11(55)

T13(65)

T14(70)

S2(6)

S4(16)

S9(47)

S11(57)

(N) indicates subrack backplane slot position

Plug-in unitposition

LK1

LK2

LK3

LK4

LK5

LK6

LK7

LK8

Inputearthlink

Port 8

Port 7

Port 6

Port 5

Port 4

Port 3

Port 2

Port 1

Port 8

Port 7

Port 6

Port 5

Port 4

Port 3

Port 2

Port 1

Port 8

Port 7

Port 6

Port 5

Port 4

Port 3

Port 2

Port 1

Port 16

Port 15

Port 14

Port 13

Port 12

Port 11

Port 10

Port 9

Port 16

Port 15

Port 14

Port 13

Port 12

Port 11

Port 10

Port 9

Port 16

Port 15

Port 14

Port 13

Port 12

Port 11

Port 10

Port 9

Ports are identified by the slot number and the instance,e.g. S4-7 indicates port 7 for unit in slot S4



75 Ω Traffic Access Module (N+1 Protection) (TN-1X)

The 75 Ω Traffic Access Module (N+1 Protection) (TN-1X), see Figure 8-2, provides sixteen type 43 coaxial connectors for eight 2048 kbit/s tributary ports (a port being a transmit/receive pair) for the TN-1X and is used when N+1 protection of the 2 Mbit/s Tributary Units is required.

Figure 8-475 Ω Traffic Access Module (N+1 Protection) (TN-1X) - front and side views

LK1

LK2

LK3

LK4

LK5

LK6

LK7

LK8

RX

2M 7

5 Ω

TA

M (

N+

1 P

RO

TE

CT

ION

)25

UJJ

0075

0GV

Z

TX

1

AC Coupled

DC Coupled

2 3

Link

1 2 3

109

87

64

53

21



8

The upper eight connectors (RX) provide the receive (input) connections. Links LK1 to LK8 on the module (see Figure 8-2) allow the coaxial cable shield of each input to be a.c. coupled (pins 2-3 linked) or d.c. coupled (pins 1-2 linked) to the electrical earth. Figure 8-3 shows the relationship between links and the 2048 kbit/s input ports. The lower eight connectors (TX) provide the transmit (output) connections. The coaxial cable shield of each output connector is d.c. coupled to the electrical earth.

The 75 Ω Traffic Access Module (TN-1X) fits into Interface Module positions T2, T3, T5, T6, T10, T11, T13, and T14 (backplane slot positions 10, 15, 25, 30, 50, 55, 65, and 70) in the SIA of the subrack. Two modules are required to provide all the necessary connectors for a 2 Mbit/s Tributary Unit.

The relationship between the 2048 kbit/s ports, the connectors on the 75 Ω Traffic Access Module (TN-1X), and the 2 Mbit/s Tributary Units is shown in Figure 8-3.

Note 1: The input earth links are applicable to the upper receive connectors only.

Note 2: A 75 Ω Tributary Unit must be fitted in the corresponding plug-in unit position if 75 Ω Traffic Access Modules are used (e.g. a 75 Ω Tributary Unit must be fitted in plug-in unit position S2 if 75 Ω Traffic Access Modules (TN-1X) are fitted in position T2 and T3).

Figure 8-575 Ω Traffic Access Module (N+1 Protection) (TN-1X) - 2 Mbit/s port allocation

Mating connectors/cablingThe 75 Ω 2048 kbit/s tributary interfaces use coaxial cables terminated with Type 43 coaxial sockets, the mating connector is coded 32C CN15 001 AAL. The preferred coaxial cable type is 3002, however, type 2002 can also be used.

Port 8

Port 7

Port 6

Port 5

Port 4

Port 3

Port 2

Port 1

Port 16

Port 15

Port 14

Port 13

Port 12

Port 11

Port 10

Port 9


T2(10)

T3(15)

T6(30)

T5(25)

T10(50)

T11(55)

T13(65)

T14(70)

S2(6)

S4(16)

S9(47)

S11(57)

(N) indicates subrack backplane slot position Po


LK1

LK2

LK3

LK4

LK5

LK6

LK7

LK8

Inputearthlink

Port 8

Port 7

Port 6

Port 5

Port 4

Port 3

Port 2

Port 1

Port 8

Port 7

Port 6

Port 5

Port 4

Port 3

Port 2

Port 1

Port 8

Port 7

Port 6

Port 5

Port 4

Port 3

Port 2

Port 1

Port 16

Port 15

Port 14

Port 13

Port 12

Port 11

Port 10

Port 9

Port 16

Port 15

Port 14

Port 13

Port 12

Port 11

Port 10

Port 9

Port 16

Port 15

Port 14

Port 13

Port 12

Port 11

Port 10

Port 9

Ports are identified by the slot number and the instance,e.g. S4-7 indicates port 7 for unit in slot S4.



75 Ω Traffic Access Module (TN-1X/S)

The 75 Ω Traffic Access Module (TN-1X/S), see Figure 8-6, provides sixteen type 43 coaxial connectors for eight 2048 kbit/s tributary ports (a port being a transmit/receive pair) for the TN-1X/S.

Figure 8-675 Ω Traffic Access Module (TN-1X/S) - front and side views

25UJJ00750H

HZ

75 Ω T

RA

FF

IC A

CC

ES

S M

OD

ULE

LK1

LK2

LK3

LK4

LK5

LK6

LK7

LK8

RX

TX

1

AC Coupled

DC Coupled

2AC3

DC

1

2AC3

DC

Link

109

87

64

53

21



8

The left-hand eight connectors (RX) provide the receive (input) connections. Links LK1 to LK8 on the module (see Figure 8-6) allow the coaxial cable shield of each input to be a.c. coupled (pins 2-3 linked) or d.c. coupled (pins 1-2 linked) to the electrical earth. Figure 8-7 shows the relationship between links and the 2048 kbit/s input ports.

The right-hand eight connectors (TX) provide the transmit (output) connections. The coaxial cable shield of each output connector is d.c. coupled to the electrical earth.

The 75 Ω Traffic Access Module (TN-1X/S) fits into Interface Module positions M1A (upper) & M1B (lower) in the SIA of the subrack. Two modules are required to provide all the necessary connectors for a 2 Mbit/s Tributary Unit. The relationship between the 2048 kbit/s ports, the connectors on the 75 Ω Traffic Access Module (TN-1X/S), and the 2 Mbit/s Tributary Unit is shown in Figure 8-7.

Note 1: The input earth links are applicable to the receive connectors only.

Note 2: A 75 Ω Tributary Unit must be fitted in the corresponding plug-in unit position (S2) if 75 Ω Traffic Access Modules (TN-1X/S) are used.

Figure 8-775 Ω Traffic Access Module (TN-1X/S) - 2 Mbit/s port allocation

Mating connectors/cablingThe module is connected to 75 Ω connector panel using thirty-two RG179 coaxial cables (25Y CN00 750 AAN). These cables are terminated with Type 43 connectors for connection to the traffic interface module and SMB connectors for connection to the connector panel.

Port 8

Port 16

LK1

Port 5

Port 13

LK4

TIM M1A(Upper)

TIM M1B(Lower)

Input earth link

Port 7

Port 15

LK2

Port 6

Port 14

LK3

Port 4

Port 12

LK5

Port 3

Port 11

LK6

Port 1

Port 9

LK8

Port 2

Port 10

LK7

Plug-in unit position S2 (subrack backplane slot position 6)



120 Ω Traffic Access Module (TN-1X)

The 120 Ω Traffic Access Module (TN-1X), see Figure 8-8, provides two 25-way ‘D’ type connectors for eight 2048 kbit/s tributary ports (a port being a transmit/receive pair) for the TN-1X and is used when N+1 protection of the 2 Mbit/s Tributary Units is required.

Figure 8-8120 Ω Traffic Access Module (TN-1X) - front and side views

INPUT

2M 1

20 Ω

TA

M (

N+

1 P

RO

TE

CT

ION

)25

UJJ

0075

0HLV

OUTPUT

1

LK1 6

6

1

LK1

LK1

AC Coupled

DC Coupled

Link

Pin 1

Pin 1

109

87

64

53

21



8

The upper male connector (INPUT) provides the receive (input) connections. Link LK1 (see Figure 8-8) allows the connector body and cable screen be d.c. coupled to the mechanical earth (pins 1-6 and 2-5 linked), a.c. coupled to the mechanical earth (pins 2-5 and 3-4 linked), or left isolated from the mechanical earth (no links fitted).

The lower female connector (OUTPUT) provides the transmit (output) connections. The connector body and the cable shield are d.c. coupled to the mechanical earth.

The 120 Ω Traffic Access Module (TN-1X) fits into Interface Module positions T2, T3, T5, T6, T10, T11, T13, and T14 (backplane slot positions 10, 15, 25, 30, 50, 55, 65, and 70) in the SIA of the subrack. Two modules are required to provide all the necessary connectors for a 2 Mbit/s Tributary Unit. The relationship between the 2048 kbit/s ports, the connectors on the 120 Ω Traffic Access Module (TN-1X), and the 2 Mbit/s Tributary Units is shown in Figure 8-9.

Figure 8-9120 Ω Traffic Access Module (TN-1X) - 2 Mbit/s port allocation

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Cable Screen

Sig 1

Sig 2

Sig 3

Sig 4

Sig 5

Sig 6

Sig 7

Sig 8

Sig 7b

Sig 8b

Sig 6b

Sig 5b

Sig 4b

Sig 1b

Sig 3b

Sig 2b

Pins 4, 7, 10, 13, 15, 18, 21, and 24 not used.

Signal Pair

Port 1

Port 2

Port 3

Port 4

Port 5

Port 6

Port 7

Port 8

Port 9

Port 10

Port 11

Port 12

Port 13

Port 14

Port 15

Port 16


T2(10)

T3(15)

T6(30)

T5(25)

T10(50)

T11(55)

T13(65)

T14(70)

S2(6)

S4(16)

S9(47)

S11(57)



Sig 7a

Sig 8a

Sig 6a

Sig 5a

Sig 4a

Sig 1a

Sig 3a

Sig 2a

Port 1

Port 2

Port 3

Port 4

Port 5

Port 6

Port 7

Port 8

Port 1

Port 2

Port 3

Port 4

Port 5

Port 6

Port 7

Port 8

Port 1

Port 2

Port 3

Port 4

Port 5

Port 6

Port 7

Port 8

Port 9

Port 10

Port 11

Port 12

Port 13

Port 14

Port 15

Port 16

Port 9

Port 10

Port 11

Port 12

Port 13

Port 14

Port 15

Port 16

Port 9

Port 10

Port 11

Port 12

Port 13

Port 14

Port 15

Port 16




Note: A 120 Ω Tributary Unit must be fitted in the corresponding plug-in unit position if 120 Ω Traffic Access Modules (TN-1X) are used (e.g. a 120 Ω Tributary Unit must be fitted in plug-in unit position S2 if 120 Ω Traffic Access Modules (TN-1X) are fitted in position T2 and T3).

Mating connectors/cablingThe module is connected to 120 Ω connector panel using cable 25Y CN00 750 AAV (2 off) and cable 25Y CN00 750 AAZ (2 off).



8

120 Ω Traffic Access Module (N+1 Protection) (TN-1X)

The 120 Ω Traffic Access Module (N+1 Protection) (TN-1X), see Figure 8-8, provides two 25-way ‘D’ type connectors for eight 2048 kbit/s tributary ports (a port being a transmit/receive pair) for the TN-1X and is used when N+1 protection of the 2 Mbit/s Tributary Units is required.

Figure 8-10120 Ω Traffic Access Module (N+1 Protection) (TN-1X) - front and side views

INPUT

120

Ω T

RA

FF

IC A

CC

ES

S M

OD

ULE

25U

JJ00

750H

LV

OUTPUT

Pin 1

Pin 1

109

87

64

53

21



The upper male connector (INPUT) provides the receive (input) connections. The connector body and cable screen be d.c. coupled to the mechanical earth.

Note: Link LK1 is not used.

The lower female connector (OUTPUT) provides the transmit (output) connections. The connector body and the cable shield are d.c. coupled to the mechanical earth.

The 120 Ω Traffic Access Module (TN-1X) fits into Interface Module positions T2, T3, T5, T6, T10, T11, T13, and T14 (backplane slot positions 10, 15, 25, 30, 50, 55, 65, and 70) in the SIA of the subrack. Two modules are required to provide all the necessary connectors for a 2 Mbit/s Tributary Unit. The relationship between the 2048 kbit/s ports, the connectors on the 120 Ω Traffic Access Module (TN-1X), and the 2 Mbit/s Tributary Units is shown in Figure 8-9.

Figure 8-11120 Ω Traffic Access Module (N+1 Protection) (TN-1X) - 2 Mbit/s port allocation

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Cable Screen

Sig 1

Sig 2

Sig 3

Sig 4

Sig 5

Sig 6

Sig 7

Sig 8

Sig 7b

Sig 8b

Sig 6b

Sig 5b

Sig 4b

Sig 1b

Sig 3b

Sig 2b

Pins 4, 7, 10, 13, 15, 18, 21, and 24 not used.

Signal Pair

Port 1

Port 2

Port 3

Port 4

Port 5

Port 6

Port 7

Port 8

Port 9

Port 10

Port 11

Port 12

Port 13

Port 14

Port 15

Port 16

InterfaceModuleposition

T2(10)

T3(15)

T6(30)

T5(25)

T10(50)

T11(55)

T13(65)

T14(70)

S2(6)

S4(16)

S9(47)

S11(57)



Sig 7a

Sig 8a

Sig 6a

Sig 5a

Sig 4a

Sig 1a

Sig 3a

Sig 2a

Port 1

Port 2

Port 3

Port 4

Port 5

Port 6

Port 7

Port 8

Port 1

Port 2

Port 3

Port 4

Port 5

Port 6

Port 7

Port 8

Port 1

Port 2

Port 3

Port 4

Port 5

Port 6

Port 7

Port 8

Port 9

Port 10

Port 11

Port 12

Port 13

Port 14

Port 15

Port 16

Port 9

Port 10

Port 11

Port 12

Port 13

Port 14

Port 15

Port 16

Port 9

Port 10

Port 11

Port 12

Port 13

Port 14

Port 15

Port 16




8

Note: A 120 Ω Tributary Unit must be fitted in the corresponding plug-in unit position if 120 Ω Traffic Access Modules (TN-1X) are used (e.g. a 120 Ω Tributary Unit must be fitted in plug-in unit position S2 if 120 Ω Traffic Access Modules (TN-1X) are fitted in position T2 and T3).

Mating connectors/cablingThe module is connected to 120 Ω connector panel using cable 25Y CN00 750 AAV (2 off) and cable 25Y CN00 750 AAZ (2 off).



120 Ω Traffic Access Module (TN-1X/S)

The 120 Ω Traffic Access Module (TN-1X/S), see Figure 8-12, provides two 25-way ‘D’ type connectors for eight 2048 kbit/s tributary ports (a port being a transmit/receive pair) for the TN-1X/S.

Figure 8-12120 Ω Traffic Access Module (TN-1X/S) - front and side views

RX

120 Ω T

RA

FF

IC A

CC

ES

S M

OD

ULE

25UJJ00750H

JA

TX

1

LK1 6

6

1

LK1

LK1

AC Coupled

DC Coupled

Link

109

87

64

53

21



8

The left-hand male connector (RX) provides the receive (input) connections. Link LK1 (see Figure 8-12) allows the connector body and cable screen be a.c. coupled to the mechanical earth (pins 1-6 and 2-5 linked), d.c. coupled to the mechanical earth (pins 2-5 and 3-4 linked), or left isolated from the mechanical earth (no links fitted).

The right-hand female connector (TX) provides the transmit (output) connections. The connector body and the cable shield are d.c. coupled to the mechanical earth.

The 120 Ω Traffic Access Module (TN-1X/S) fits into Interface Module positions M1A & M1B in the SIA of the subrack. Two modules are required to provide all the necessary connectors for a 2 Mbit/s Tributary Unit. The relationship between the 2048 kbit/s ports, the connectors on the 120 Ω Traffic Access Module (TN-1X/S), and the 2 Mbit/s Tributary Unit is shown in Figure 8-13.

Figure 8-13120 Ω Traffic Access Module (TN-1X/S) - 2 Mbit/s port allocation

Note: A 120 Ω Tributary Unit must be fitted in the corresponding plug-in unit position (S2) if 120 Ω Traffic Access Modules (TN-1X/S) are used.

Sig 1

Sig 2

Sig 3

Sig 4

Sig 5

Sig 6

Sig 7

Sig 8

Pins 4, 7, 10, 13, 15, 18, 21, and 24 not used.

Signal Pair

Port 1

Port 2

Port 3

Port 4

Port 5

Port 6

Port 7

Port 8

Port 9

Port 10

Port 11

Port 12

Port 13

Port 14

Port 15

Port 16


M1A(Upper)

M1B(Lower)

Plug-in unit position S2(subrack backplane slot position 6)

1 2 3 4 5 6 7 8 9 10 11 12 13

14 15 16 17 18 19 20 21 22 23 24 25

13 12 11 10 9 8 7 6 5 4 3 2 1

25 24 23 22 21 20 19 18 17 16 15 14

Dra

in w

ire

Trib

. 7

Trib

. 8

Trib

. 6

Trib

. 5

Trib

. 4

Trib

. 1

Trib

. 3

Trib

. 2

Dra

in w

ire

Trib

. 7

Trib

. 8

Trib

. 6

Trib

. 5

Trib

. 4

Trib

. 1

Trib

. 3

Trib

. 2

Input tributaries (male panel connector)

Output tributaries (female panel connector)



Mating connectors/cablingInputThe left-hand 25-way male ‘D’ type connector (RX) provides the receive connections, the mating connector is coded 32C CN16 100 AJH.

OutputThe right-hand 25-way female ‘D’ type connector (TX) provides the transmit connections, the mating connector is coded 32C CN36 100 AKU.



8

High Speed Traffic Access Module

The High Speed Traffic Access Module, see Figure 8-14, provides two type 43 coaxial connectors for a 34,368 kbit/s 75 Ω electrical aggregate port (a port being a transmit/receive pair) and a coaxial connector for monitoring the output signal. The module is not applicable to the TN-1X/S.

Figure 8-14High Speed Traffic Access Module - front and side views

HIG

H S

PE

ED

TR

AF

FIC

AC

CE

SS

MO

DU

LE25

UJJ

0075

0HT

D

TX

RX

MON

109

87

64

53

21



The upper connector (MON) provides a coaxial connector for monitoring the output signal. The terminated output provides a signal 20 dB lower than the interface signal (nominal pulse height +0.1 V ± 0.01 V).

The middle connector (TX) provides the transmit (output) connection. The coaxial cable shield of the output connector is d.c. coupled to the electrical earth.

The lower connector (RX) provides the receive (input) connection.The coaxial cable shield of the output connector is d.c. coupled to the electrical earth.

The High Speed Traffic Access Module fits into Interface Module positions T3, T6, T11, T11, and T14 (backplane slot positions 15, 30, 55, and 70) in the SIA of the subrack. The allocation of modules to 34 Mbit/s Tributary Units is as follows:

Position T3 34 Mbit/s Tributary Unit fitted to plug-in unit position S2 (backplane slot position 6).




Mating connectors/cablingThe 34,368 kbit/s electrical aggregate ports use coaxial cables terminated with Type 43 coaxial sockets, the mating connector is coded 32C CN15 001 AAE. The preferred coaxial cable type is 2003.



8

High Speed Aggregate Module

The High Speed Aggregate Module, see Figure 8-15, provides two type 43 coaxial connectors for a 155,552 kbit/s (STM-1) electrical aggregate port (a port being a transmit/receive pair). The module is not applicable to the TN-1X/S.

Figure 8-15High Speed Aggregate Module - front and side views

HIG

H S

PE

ED

AG

G M

OD

ULE

25U

JJ00

750G

YZ

TX

RX

109

87

64

53

21



The upper connector (TX) provides the transmit (output) connection. The coaxial cable shield of the output connector is d.c. coupled to the electrical earth.


The High Speed Aggregate Unit fits into Interface Module positions T7 and T9 (backplane slot positions 35 and 45) in the SIA of the subrack. The module in Interface Module position T7 provides the high speed port for the STM-1 Electrical Aggregate Unit in plug-in unit position S6 (backplane slot position 26). The module in Interface Module position T9 provides the high speed port for the STM-1 Electrical Aggregate Unit in plug-in unit position S7 (backplane slot position 34).

Mating connectors/cablingThe 155,520 kbit/s (STM-1) electrical aggregate ports use coaxial cables terminated with Type 43 coaxial sockets, the mating connector is coded 32C CN15 001 AAE. The preferred coaxial cable type is 2003.



8

High Speed Tributary Module

The High Speed Tributary Module, see Figure 8-16, provides two type 43 coaxial connectors for a 155,552 kbit/s (STM-1) electrical tributary port (a port being a transmit/receive pair). The module is not applicable to the TN-1X/S.

Figure 8-16High Speed Tributary Module - front and side views

HIG

H S

PE

ED

TR

IB M

OD

ULE

25U

JJ00

750G

WY

TX

RX

109

87

64

53

21



The upper connector (TX) provides the transmit (output) connection. The coaxial cable shield of the output connector is d.c. coupled to the electrical earth.


The High Speed Tributary Unit fits into Interface Module positions T3, T6, T11, and T14 (backplane slot positions 10, 30, 55, and 70) in the SIA of the subrack. The allocation of modules to STM-1 Electrical Tributary Units is as follows:

Position T3 STM-1 Electrical Tributary Unit fitted to plug-in unit position S2 (backplane slot position 6).




Mating connectors/cablingThe 155,520 kbit/s (STM-1) electrical tributary ports use coaxial cables terminated with Type 43 coaxial sockets, the mating connector is coded 32C CN15 001 AAE. The preferred coaxial cable type is 2003.



8

Station Service Module

The Station Service Module, see Figure 8-17, provides connectors for the rack alarm bus, the management Q3 port (LAN), and power for the TN-1X.

Figure 8-17Station Service Module - front and side views

RACKALARM

ST

N S

ER

VIC

E M

OD

ULE

25U

JJ00

750H

LV

POWERINPUT

P1

Earth strappingpins

LAN

P3 P8

P7P2 P4

P6P5

1

4

3

2

109

87

64

53

21



The upper connector (RACK ALARM) is a male 15-way ‘D’ type which provides the connections to the rack alarm bus. The connector body and cable shield are d.c coupled to the mechanical earth. The connector clamps onto a 10-way ribbon cable. The pin-out of the connector is detailed in Table 8-2.

The middle connector (LAN) is a female 15-way ‘D’ type which provides the Attachment Unit Interface (AUI) Ethernet connection to the network management system. The connector body and cable shield are d.c. coupled to the mechanical earth. The inner signal shields are d.c. coupled to the electrical earth. The pin-out of the connector is detailed in Table 8-3.

The lower connector (POWER) is a 4-way BIC BT Type 237 connector which provides the connections for two input power supplies. The pin-out of the connector is detailed in Table 8-4.

Table 8-2Station Service Module - rack alarm connector pin-out


12345678

-12 VPrompt alarmDeferred alarmIn Station alarmNot used0 V0 V0 V

9101112131415

Not usedReceive attentionNot usedFault clearNot used0 V0 V

Table 8-3Station Service Module - LAN connector pin-out


12345678

Control In Circuit Shield (0V)Control In Circuit A (CI-A)Data Out Circuit A (DO-A)Data In Circuit Shield (0V)Data In Circuit A (DI-A)Voltage Common (VC)Control Out Circuit A (CO-A)Control Out Circuit Shield (0V)

9101112131415Shell

Control In Circuit B (CI-A)Data Out Circuit B (DO-B)Data Out Circuit Shield (0V)Data In Circuit B (DI-B)Voltage Plus (VP)Voltage Shield (VS)Control Out Circuit B (CO-B)Protective Ground (PG)

Table 8-4Station Service Module - power connector pin-out

Pin Function

1234

-48 V (fuse 1)0 V (fuse 1)0 V (fuse 2)-48 V (fuse 2)

12345678

9101112131415

87654321

1514131211109



8

The module contains eight strapping pins, P1 to P8 (see Figure 8-17), which allow the mechanical and two electrical signal earths to be linked. Table 8-5 details the earth strapping options.

The Station Service Module fits into Interface Module position T16 (backplane slot position 80) in the SIA of the subrack.

Mating connectors/cablingRack alarmThe rack alarm bus is a 10-way ribbon cable assembly which connects to the rack alarm unit via a 15-way ‘D’ type connector and runs down the right hand side rack cable space.

Buckles are used to make loops in the cable at regular intervals. Connections for the subracks are made at the end of the loops using the 15-way ‘D’ type connector.

LANThe cable between the LAN transceiver and the subrack, known as the drop cable, uses a 15-way cable. One end of this cable is terminated with a female ‘D’ type connector which engages with the LAN transceiver, the other end is terminated with a male ‘D’ type connector which engages with LAN connector on the Station Service Module. The ‘D’ type connector at the TN-1X end is terminated with plug which has a suitable slide retention compliant with IEC 807.2.

The Ethernet port requires a +12 V supply. This is obtained from the subrack Power Unit. The power consumption of the LAN transceiver is less than 0.5 A at +12 V.

PowerThe POWER connector mates with a rack power cables terminated with a flying socket. The socket comprises a moulding (25P SK00 001 AAF) and four power pins 2A (25P CN00 002 AAG).

Table 8-5Station Service Module - earth strapping options

Earthing Option Straps

For common 0 V (Fuse 1) and 0 V (Fuse 2)For common signal earth and 0 V (Fuse 1)For common signal earth and 0 V (Fuse 2)For common signal earth, 0 V (Fuse 1), and 0 V (Fuse 2)For isolated signal earth (signal earth is still referenced to 0 V (Fuse 1) by a 10 MΩ resistor)

Strap P1 to P3Strap P2 to P4, and P5 to P6Strap P3 to P4. and P5 to P6Strap P1 to P3, P2 to P4, and P5 to P6Leave P5 to P6 unstrapped; strap P7 to P8, and P2 to P4. 0 V (Fuse 1) and 0 V (Fuse 2) may still be commoned, if required, by strapping P1 to P3.



75 Ω Star Card

The 75 Ω Star Card, see Figure 8-18, provides two type 43 coaxial connectors for the external 2048 kHz timing signal ports for the TN-1X.

Figure 8-1875 Ω Star Card - front and side views

LK1

75 Ω

STA

R C

AR

D25

UJJ

0075

0GW

Z

TXCLK

1

AC Coupled

DC Coupled

2AC3

DC

1

2AC3

DC

Link

RXCLK

109

87

64

53

21



8

The upper connector (RX CLK) provides the receive (input) connection. Link LK1 on the module (see Figure 8-18) allows the cable shield of the input to be a.c. coupled to the electrical earth (pins 2 to 3 linked), or d.c. coupled to the electrical earth (pins 1 to 2 linked).

The lower connector (TX CLK) provides the transmit (output) connections. The coaxial cable shield of the output connector is d.c. coupled to the electrical earth.

The 75 Ω Star Card fits into Interface Module position T8 (backplane slot position 40) in the SIA of the subrack.

Mating connectors/cablingThe 75 Ω external timing signal ports use coaxial cables terminated with Type 43 coaxial sockets, the mating connector is coded 32C CN15 001 AAL. The preferred coaxial cable type is 3002, however, type 2002 can also be used



Flexible Termination Module

The Flexible Termination Module fills the empty position in the SIA below the Power & LCAP module on the TN-1X/S and maintains EMC screening.

Figure 8-19Flexible Termination Module - front and side views

FLEX TERM. SIM 25UJJ00750HJD1098764 532 1



8


The Flexible Access Module, see Figure 8-20, provides the connections for LCAP on the TN-1X.

Figure 8-20Flexible Access Module - front and side views

LCAP

FLE

XIB

LE A

CC

ES

S M

OD

ULE

25U

JJ00

750G

WX

109

87

64

53

2 1



The connection to Local Craft Access Panel is provided by a 25-way ‘D’ type connector (LCAP), no external connections are provided by the unit. This connector provides connections for the following:

• RS232 local terminal interface

• receive attention control

• Subrack Controller LEDs

• Engineering Order Wire phone

• low speed traffic monitor points (future facility)

Mating connectors/cablingCableform assembly 25Y CN00 021 AAA (part of the LCAP assembly) provides the connection between the module and the Local Craft Access Panel. The Flexible Access Module fits into Interface Module position T1 (backplane slot position 1) in the SIA of the subrack.



8

Power & LCAP Module

The Power & LCAP Module provides the primary d.c. power feed into the TN-1X/S subrack and the connection to the EOW/CATT connector panel.

Figure 8-21Power & LCAP Module - front and side views

Power inputThe Power connector is a 4-way BIC BT Type 237 connector which provides the connections for two input power supplies. The pin-out of the connector is detailed in Table 8-6.

The module contains eight strapping pins, P1 to P8 (see Figure 8-22), which allow the mechanical and two electrical signal earths to be linked. Table 8-7 details the earth strapping options.

Table 8-6Power & LCAP Module - power connector pin-out

Pin Function

1234

-48 V (fuse 1)0 V (fuse 1)0 V (fuse 2)-48 V (fuse 2)

POWER

POWER & LCAP SIM 25UJJ00750HJB

LCAP1098764 532 1



Figure 8-22Power & LCAP Module - earth strapping pins

EOW/CATT connectionA 25-way ‘D’ type socket provides the following through-connections to the EOW/CATT connector panel:

• RS-232C local terminal (CATT) interface

• Receive attention control



• Traffic monitor point (future facility; currently terminated on the EOW/CATT connector panel).

The pin-out of the connector is detailed in Table 8-8.

Table 8-7Power & LCAP Module- earth strapping options

Earthing Option Straps

For common 0 V (Fuse 1) and 0 V (Fuse 2)For common signal earth and 0 V (Fuse 1)For common signal earth and 0 V (Fuse 2)For common signal earth, 0 V (Fuse 1), and 0 V (Fuse 2)For isolated signal earth (signal earth is still referenced to 0 V (Fuse 1) by a 10 MΩ resistor)

Strap P1 to P3Strap P2 to P4, and P5 to P6Strap P3 to P4. and P5 to P6Strap P1 to P3, P2 to P4, and P5 to P6Leave P5 to P6 unstrapped; strap P7 to P8, and P2 to P4. 0 V (Fuse 1) and 0 V (Fuse 2) may still be commoned, if required, by strapping P1 to P3.

P8 P7 P6

P3 P4 P5

P1 P2

C2

C11



8

Note: The local terminal may be connected directly to this socket provided only the pins shown in white in Table 8-8 are connected: the other signals might interfere with the operation of the RS-232C port.

Mating connectors/cablingEOW/CATTCableform assembly 25Y CN00 750 AAQ is used to connect between the Power & LCAP module and the EOW/CATT connector panel.

PowerThe POWER connector mates with a rack power cables terminated with a flying socket. The socket comprises a moulding (25P SK00 001 AAF) and four power pins 2A (25P CN00 002 AAG).

Table 8-8Power & LCAP Module - EOW/CATT connector pin-out


12345678910111213

Signal ground (0 V)Transmit data (TXD)Receive data (RXD)Ready to send (RTS)Clear to send (CTS)Data set ready (DSR)Signal ground (0 V)Signal ground (0 V)+5 V o/pDetect terminalSignal ground (0 V)EOW B +veMonitor point +ve

141516171819202122232425

EOW A +veEOW A -veReceive ATT switchReceive ATT switch (0 V)General Alarm LED anodeGeneral Alm LED cathodeData transmit ready (DTR)Receive ATT LED anodeReceive ATT LED cathodeSignal ground (0 V)EOW B -veMonitor point -ve

12345678910111213

141516171819202122232425



Flexible Access Module (External Alarms)

The Flexible Access Module (External Alarms), see Figure 8-23, provides the connections for LCAP on the TN-1X and up to 5 external alarms on the TN-1X.

Figure 8-23Flexible Access Module (External Alarms) - front and side views

LCAP

FLE

XIB

LE A

CC

ES

S M

OD

ULE

25U

JJ00

750H

PD

EXTERNAL ALARM

109

87

64

53

2 1



8

The upper connector (LCAP) is a female 25-way ‘D’ type connector which provides the connection to Local Craft Access Panel. This connector provides connections for the following:

• RS232 local terminal interface

• receive attention control



• low speed traffic monitor points (future facility)

The lower connector (EXTERNAL ALARM) is a male 25-way ‘D’ type which provides the connections for up to 5 external alarm inputs. The connector body and cable shield are d.c. coupled to the mechanical earth. The pin-out of the connector is detailed in Table 8-9.

The Flexible Access Module (External Alarms) fits into Interface Module position T1 (backplane slot position 1) in the SIA of the subrack.

Mating connectors/cablingLCAPCableform assembly 25Y CN00 021 AAA (part of the LCAP assembly) provides the connection between the module and the Local Craft Access Panel.

EXTERNAL ALARMThe lower 25-way male ‘D’ type connector (ALARMS) provides the external alarms connections, the mating connector is coded 32C CN16 100 AJH.

Table 8-9Flexible Access Module (External Alarms) - external alarm connector pin-out


12345678910111213

External alarm input 1





Not usedNot usedMechanical earth

141516171819202122232425

Not usedNot usedNot usedNot usedNot usedNot usedNot usedNot usedNot usedNot usedNot usedNot used

12345678910111213

141516171819202122232425



External Alarm Module

The External Alarm Module, see Figure 8-24, provides the connections for up to 5 external alarms on the TN-1X/S.

Figure 8-24External Alarms Module - front and side views

The external alarm connector (EXTERNAL ALARM) is a male 25-way ‘D’ type which provides the connections for up to 5 external alarm inputs. The connector body and cable shield are d.c. coupled to the mechanical earth. The pin-out of the connector is detailed in Table 8-9.

Table 8-10External Alarm Module - external alarm connector pin-out


12345678910111213






Not usedNot usedMechanical earth

141516171819202122232425

Not usedNot usedNot usedNot usedNot usedNot usedNot usedNot usedNot usedNot usedNot usedNot used

EXTERNAL ALARM 25UJJ00750HPF

EXTERNAL ALARM

1098764 532 1

12345678910111213

141516171819202122232425



8

The External Alarm Module fits into the Interface Module position below the Power & LCAP Module.

Mating connectors/cablingThe 25-way male ‘D’ type connector (EXTERNAL ALARM) provides the external alarms connections, the mating connector is coded 32C CN16 100 AJH.

CAUTIONExternal Alarm Module removal/insertionSpurious alarms may result if the External Alarm Module is removed or inserted whilst monitoring of external alarms is enabled, but this action shall not cause loss of service or damage to equipment.

The External Alarm Module must not be inserted into a operating multiplexer with the external alarm connector already fitted.

Electrical protectionThe External Alarm Module external alarm inputs provide connection against connection to a battery supply in the range of 40 V to 72 V, no protection is provided for battery surge, lightening pulse or mains voltages. All external equipment connected to the alarm inputs should provide protection from mains voltages in accordance with the requirements of EN 41003 for connection to Telecommunication Network Voltage (TNV) circuits. In the event of high voltages (>TNV) appearing at the external alarm inputs, the External Alarm Module may need to be replaced.

External alarm integrityIt is not possible to guarantee the integrity of the end-to-end transmission link, therefore external alarms are only reported remotely if the transmission link is maintained. The external alarms should not be used for life dependent or hazardous activities.



75 Ω Connector Panel

The 75 Ω Connector Panel provides SMB connections for sixteen 2 Mbit/s 75 Ω tributary ports (both reception and transmission) on the TN-1X/S.

Figure 8-2575 Ω Connector Panel

Note: The order of the reception and transmission connectors depends upon the order the connections are made from the Traffic Access Modules to the connector panel. Figure 8-26 is a suggestion of the order to make the connections.

Figure 8-2675 Ω Connector Panel - suggested port connections

Mating connectors/cablingThe connector panel is connected to the Traffic Access Module using 32 cables of type 25Y CN00 750 AAN.

The 75 Ω 2048 kbit/s tributary interfaces use coaxial cables terminated with SMB coaxial sockets, the mating cable is coded 32Y CN00 693 AAA-AAK.

R TR T

RX TX

RX TX8 (M1A)

9 (M1B)

7 (M1A)6 (M1A)

5 (M1A)

16 (M1B)15 (M1B)

14 (M1B)13 (M1B)

10 (M1B)11 (M1B)

12 (M1B)

4 (M1A)3 (M1A)

2 (M1A)1 (M1A)

8 (M1A)

9 (M1B)

7 (M1A)6 (M1A)

5 (M1A)

16 (M1B)15 (M1B)

14 (M1B)13 (M1B)

10 (M1B)11 (M1B)

12 (M1B)

4 (M1A)3 (M1A)

2 (M1A)1 (M1A)



8

120 Ω Connector Panel

The 120 Ω Connector Panel provides four 25-way D-type connections for sixteen 2 Mbit/s 120 Ω tributary ports (both reception and transmission) on the TN-1X/S).

Figure 8-27120 Ω Connector Panel

Note: The order of the reception and transmission connectors depends upon the order the connections are made from the Traffic Access Modules to the connector panel. Figure 8-26 is a suggestion of the order to make the connections.

Figure 8-28120 Ω Connector Panel - connector pin allocation

RX TX

Sig 1

Sig 2

Sig 3

Sig 4

Sig 5

Sig 6

Sig 7

Sig 8

Pins 4, 7, 10, 13, 15, 18, 21, and 24 not used.

Signal Pair

Port 1

Port 2

Port 3

Port 4

Port 5

Port 6

Port 7

Port 8

Port 9

Port 10

Port 11

Port 12

Port 13

Port 14

Port 15

Port 16


M1A(Upper)

M1B(Lower)

Plug-in unit position S2(subrack backplane slot position 6)

1 2 3 4 5 6 7 8 9 10 11 12 13

14 15 16 17 18 19 20 21 22 23 24 25

13 12 11 10 9 8 7 6 5 4 3 2 1

25 24 23 22 21 20 19 18 17 16 15 14

Dra

in w

ire

Trib

. 7

Trib

. 8

Trib

. 6

Trib

. 5

Trib

. 4

Trib

. 1

Trib

. 3

Trib

. 2

Dra

in w

ire

Trib

. 7

Trib

. 8

Trib

. 6

Trib

. 5

Trib

. 4

Trib

. 1

Trib

. 3

Trib

. 2

Input tributaries (male panel connector)

Output tributaries (female panel connector)



Figure 8-29120 Ω Connector Panel - suggested port connections

Mating connectors/cablingThe connector panel is connected to the Traffic Access Module using 4 cables of type 25Y CN00 750 AAV.

InputThe left-hand 25-way male ‘D’ type connectors (RX) provide the receive connections, the mating connector is coded 32C CN16 100 AJH.

OutputThe right-hand 25-way female ‘D’ type connectors (TX) provide the transmit connections, the mating connector is coded 32C CN36 100 AKU.

RX TX

M1BM1A M1A M1B



8

EOW/CATT Connector Panel

The EOW/CATT connector panel is mounted on the right-hand side of the fibre tray, behind the hinged cover. It provides the following:

• local terminal interface connection via a 25-way D-type connector.

• EOW interface connection via a BT Type 603A socket.

• Receive attention control.

• Subrack Controller LEDs.

Figure 8-30EOW/CATT Connector Panel - front view

The local terminal port is a female 25-way ‘D’ type connector. The pin-out of the connector is detailed in Table 8-8.

The subrack alarm facilities are provided by a receive attention push-button switch (‘REC ATT’), and two LEDs (red ‘ALM’, green ‘ACK’). These facilities are controlled by the Subrack Controller.

Table 8-11EOW/CATT Connector Panel - local terminal connector pin-out


12345678910111213

Frame ground (0 V)Transmit data (TXD)Receive data (RXD)Ready to send (RTS)Clear to send (CTS)Data set ready (DSR)Signal ground (0 V)No connection+5 V (not used)Detect terminalNo connectionNo connectionNo connection

141516171819202122232425

No connectionNo connectionNo connectionNo connectionNo connectionNo connectionData transmit ready (DTR)No connectionNo connectionNo connectionNo connectionNo connection

CATT

Behind hinged cover

EOW

REC ATTACKALM

12345678910111213

141516171819202122232425



Mating connectors/cablingThe local terminal port (CATT) is an RS232C interface using a 25-way ‘D’ Type socket. The cable must be terminated at the TN-1X end with plug type 32C CN36 100 AKU and 4.40 UNC screws. The cable and connector to the local terminal will depend on which type of local terminal device is used and is therefore customer specific. Cableform 25Y CN00 748 AAA provides suitable cabling and connectors when using a local terminal fitted with a 9-way ‘D’ type connector.

A CW1311 type phone jack socket (EOW) is provided for connection of the DTMF handset for Engineering Order Wire operation.

The EOW/CATT connector panel is connected to the SIM Type 40S Power & LCAP module using a cable with 25-way ‘D’ type connectors (cableform 25Y CN00 750 AAQ). The connector body and cable shield are d.c. coupled to the mechanical earth.



8

Cabling and connector arrangements

TN-1X subrackExternal cabling normally enters the rack at the top or bottom and runs in the cable space at the sides of the rack. Cable support features are provided.

Common rack wiring, that is the power supply, rack alarm bus, and network management bus cables, are normally located in the right hand cable space. Traffic cabling can be located in the left hand space or the right hand space.

The cables gain access to the SIA of the subrack via the cut away sections in the subrack sideplates. The connectors are mounted on the front of the Interface Modules.

Figure 8-31 shows typical cable grooming for a subrack with 75 Ω 2048 kbit/s interfaces. Figure 8-32 shows typical cable grooming for a subrack with 120 Ω 2048 kbit/s interfaces.

TN-1X/S subrackThe cabling arrangement will depend upon the installation. Power is connected to the Power & LCAP SIM in the SIA. Incoming tributaries are connected to the connector panel at the lower front of the subrack.

Figure 8-33 shows typical cable grooming for a subrack with 75 Ω 2048 kbit/s interfaces.

Figure 8-34 shows typical cable grooming for a subrack with 120 Ω 2048 kbit/s interfaces.

Tributary connectionsTributaries are connected to the subrack via the lower connector panel. The connector panel brings the connection point to the front of the subrack to simplify connection of tributary cables. The connector panel has two positions (see Figure 8-35). The forward position is used whilst the incoming and outgoing tributary cables are being wired to the subrack. The panel is then moved to the rearward position. The special extended screws are threaded at two points to allow the connector panel to be fixed in either position.

It is recommended that the tributary cables be dressed to the right-hand side of the rack because the optical fibres have to be dressed to the left-hand side.

The connector panel is connected to the TIMs by individual cables.



Figure 8-31TN-1X 75 Ω traffic cable grooming

2M TRIB(75 Ω)

P/LOADMNGR

POWERUNIT

SBRKCONT

STM1OPTAGG

Note: Shown with SIA cover removed

STM1OPTAGG

P/LOADMNGR

POWERUNIT

BLANKMODULE

BLANKMODULE

FAIL FAIL FAIL FAIL FAIL FAIL FAIL FAIL FAIL FAIL FAIL

SHELFPOSITION

21

RECEIVE ATT

25U

JU00

750G

XG

BLANKMODULE

ALARM ALM ACKESD

2M TRIB(75 Ω)

2M TRIB(75 Ω)

2M TRIB(75 Ω)

1 2 3 4 5 6 7 8 9 10

11 12

13

14

25U

JU00

750G

XG

25U

JU00

750G

XG

25U

JU00

750G

XG

25R

BN

0002

1AA

B

25R

BN

0002

1AA

B

25R

BN

0002

1AA

B

25U

TM

0075

0GW

A

25U

TM

0075

0GW

A

25U

PJ0

0750

GX

F

25U

PJ0

0750

GX

F

25U

PW

0075

0HA

Y

25U

PW

0075

0HA

Y

25U

MN

0075

0G

XD



8

Figure 8-32TN-1X 120 Ω traffic cable grooming

2M TRIB(120 Ω)

P/LOADMNGR

POWERUNIT

SBRKCONT

STM1OPTAGG

Note: Shown with SIA cover removed

STM1OPTAGG

P/LOADMNGR

POWERUNIT

BLANKMODULE

BLANKMODULE

FAIL FAIL FAIL FAIL FAIL FAIL FAIL FAIL FAIL FAIL FAIL

SHELFPOSITION

21

BLANKMODULE

2M TRIB(120 Ω)

2M TRIB(120 Ω)

2M TRIB(120 Ω)

1 2 3 4 5 6 7 8 9 10

11 12

13

14

RECEIVE ATTALARM ALM ACK

ESD

25U

JU00

750G

XR

25R

BN

0002

1AA

B

25R

BN

0002

1AA

B

25R

BN

0002

1AA

B

25U

TM

0075

0GW

A

25U

TM

0075

0GW

A

25U

PJ0

0750

GX

F

25U

PJ0

0750

GX

F

25U

PW

0075

0HA

Y

25U

PW

0075

0HA

Y

25U

MN

0075

0G

XD

25U

JU00

750G

XR

25U

JU00

750G

XR

25U

JU00

750G

XR



Figure 8-33TN-1X/S 75 Ω traffic cable grooming

Figure 8-34TN-1X/S 120 Ω traffic cable grooming

2M TRIB(75 Ω)

P/LOADMNGR

POWERUNIT

SBRKCONT

STM1OPTAGG

STM1OPTAGG

P/LOADMNGR

POWERUNIT

BLANKMODULE

BLANKMODULE

FAIL FAIL FAIL FAIL FAIL FAIL FAIL FAIL

25U

JU00

750G

XG

1 2 3 4 5 6 7 8 9 10

11 12

13

14

25R

BN

0002

1AA

B

25R

BN

0002

1AA

B

25U

TM

0075

0GW

A

25U

TM

0075

0GW

A

25U

PJ0

0750

GX

F

25U

PJ0

0750

GX

F

25U

PW

0075

0HA

Y

25U

PW

0075

0HA

Y

25U

MN

0075

0G

XD

RX

RX

TX

TX

BLANKMODULE

25R

BN

0002

1AA

B

BLANKMODULE

25R

BN

0002

1AA

B

BLANKMODULE

25R

BN

0002

1AA

B

BLANKMODULE

25R

BN

0002

1AA

B

2M TRIB(120 Ω)

P/LOADMNGR

POWERUNIT

SBRKCONT

STM1OPTAGG

STM1OPTAGG

P/LOADMNGR

POWERUNIT

BLANKMODULE

BLANKMODULE

FAIL FAIL FAIL FAIL FAIL FAIL FAIL FAIL

25U

JU00

750G

XR

1 2 3 4 5 6 7 8 9 10

11 12

13

14

25R

BN

0002

1AA

B

25R

BN

0002

1AA

B

25U

TM

0075

0GW

A

25U

TM

0075

0GW

A

25U

PJ0

0750

GX

F

25U

PJ0

0750

GX

F

25U

PW

0075

0HA

Y

25U

PW

0075

0HA

Y

25U

MN

0075

0G

XD

RX TX

BLANKMODULE

25R

BN

0002

1AA

B

BLANKMODULE

25R

BN

0002

1AA

B

BLANKMODULE

25R

BN

0002

1AA

B

BLANKMODULE

25R

BN

0002

1AA

B



8

Figure 8-35Connector panel forward and rearward positions

Optical connectionsThe optical signal cables connect directly to FC-PC type optical connectors on the front panels of the optical units. The optical cables lay in a tray, which contains retaining clips, mounted at the bottom of the plug-in unit (see Figure 8-31 to Figure 8-34). The upper connector (RX) is the receive connector, the lower connector (TX) is the transmit connector.

The optical connectors on the front of the optical unit are protected by a hinged cover. For safety reasons, this cover can only be opened when the unit is not fully inserted into the subrack (the front panel of the adjacent unit preventing the cover from opening). This prevents access to the optical connectors whilst the unit is powered-up and an optical output signal is present.

CAUTION

Do not attempt to force open the cover whilst the unit is fully inserted into the subrack.

Connector panel in forward position for connecting the tributary cables.

Connector panel in rearward position.



LAN connectionsThe Nortel TN-1X and the TN-MS management systems are designed for interconnection via 10 Mbit/s CSMA/CD (Ethernet-type) LANs. The Nortel TN-1X and the TN-MS management systems are supplied with standard LAN interfaces which conform to Ethernet, IEEE 802.3 and ISO 8802-3.

There are a number of physical options for the LAN infrastructure itself (i.e. external LAN equipment to which the Nortel TN-1X and the TN-MS management systems attach). For use in a telecommunications environment, a medium with good electromagnetic compatibility is essential, the following are recommended:

• 10BaseT - 10 Mbit/s twisted pair baseband cabling (using a central LAN ‘hub’).

• 10Base5 - 10 Mbit/s thick coaxial baseband cabling

For most purposes, 10BaseT provides the more cost-effective and easily implemented solution.

10Base5 was the original Ethernet medium but is generally more expensive and harder to install than 10BaseT. If the current installations use 10Base5, it is recommended that 10BaseT is used when extending the LAN. This can be effected through the use of a 10BaseT hub, connected directly or via a repeater to the thick coax segment.

Extension of the LAN within a local site, beyond the distance span of a single segment, may be achieved by repeaters or local Bridges/Routers. Remote Bridges/Routers provide a means of extending the LAN across geographically separated sites. For extension of a LAN between two sites up to a few kilometers apart, where there are spare fibres between the sites, Fibre Optic Inter Repeater Links (FOIRL) can also be used to interconnect LAN segments on the two sites.

end of chapter


9-1

9

Equipment codes 9-Unit codes

Each unit has a unique 13-digit code. Each type of unit may have more than one variant in order to cater for specific customer requirements (e.g. front panel language), each of the variants has a separate 13-digit/8-digit code. Table 9-1 details the currently available plug-in units. Table 9-2 details the currently available Interface Modules on the TN-1X, Table 9-3 details the currently available Interface Modules on the TN-1X/S. Table 9-4 details the currently available Connector Panels on the TN-1X/S.

Table 9-1Plug-in unit codes

Unit Type CodeApplicability

TN-1X TN-1X/S

Power Unit 120 W 25U PW00 750 HAY √ √

Power Unit 150 W 25U PW00 750 HSY √ √

Subrack Controller 25U MN00 750 GXD √ √

Payload Manager 25U PJ00 750 GXF √ √

Payload Manager (TSI-2) 25U PJ00 750 HZQ √ √

Payload Manager (Mixed Payload) NTKD10AA √ √

STM-1 Optical Aggregate Unit 25U TM00 750 GWA √ √

STM-1 Optical Aggregate Unit - Long/Short Haul 25U TM00 750 HWF √ √

STM-1 Electrical Aggregate Unit 25U TM00 750 GWB √

2 Mbit/s Tributary Unit 75 Ω 25U JU00 750 GXG √ √

2 Mbit/s Tributary Unit 120 Ω 25U JU00 750 GXR √ √

2 Mbit/s Tributary Unit 75 Ω 25U JU00 750 HVT √ √

2 Mbit/s Tributary Unit 120 Ω 25U JU00 750 HVQ √ √

34 Mbit/s Tributary Unit 25U JU00 750 HJZ √

STM-1 Optical Tributary Unit 2” 25U JU00 750 GVA √ √

—continued—


9-2 Equipment codes

STM-1 Optical Tributary Unit 1” 25U TM00 750 HWE √ √

STM-1 Optical Tributary Unit 1” (TSI-2) 25U TM00 750 HWG √ √

STM-1 Optical Tributary 1” (Mixed Payloads) NTKD11AA √ √

STM-1 Electrical Tributary Unit 2” 25U JU00 750 GVB √

STM-1 Electrical Tributary Unit 2” (TSI-2) 25U JU00 750 JBK √

STM-1 Electrical Tributary 1” (Mixed Payloads) NTKD12AA √

Local Craft Access Panel 75 Ω 25U EP00 750 GXB √

STM-4 Optical Aggregate Unit - Long Haul (1310 nm) 25U TM00 750 GSA √ √

STM-4 Optical Aggregate Unit - Intra-Office (1310 nm) 25U TM00 750 GSC √ √

STM-4 Optical Aggregate Unit - Long Haul (1550 nm) 25U TM00 750 HVB √

EOW Unit (ICC1) 25U SV00 750 GVX √ √

EOW Unit (ICC2) NTKD13AA √ √

EOW Handset Kit 25S KM00 750 HZM √

—end—

Table 9-2TN-1X Interface Module codes

Interface Module Code

75 Ω Traffic Access Module 25U JJ00 750 GVZ

75 Ω Traffic Access Module (N+1 Protection) NTKD14AA

120 Ω Traffic Access Module 25U JJ00 750 HLV

120 Ω Traffic Access Module (N+1 Protection) NTKD15AA

High Speed Traffic Access Module 25U JJ00 750 HTD

High Speed Aggregate Module 25U JJ00 750 GYZ

High Speed Tributary Module 25U JJ00 750 GWY

Station Service Module 25U JJ00 750 GXC

75 Ω Star Card 25U JJ00 750 GWZ

Flexible Access Module 25U JJ00 750 GWX

Flexible Access Module - Ext Alarms 25U JJ00 750 HPD

Table 9-1Plug-in unit codes (continued)

Unit Type CodeApplicability

TN-1X TN-1X/S


Equipment codes 9-3

9

TN-1X subrack codesEach TN-1X equipped subrack comprises an unequipped subrack (25G MU00 750 GWV) and the required complement of plug-in units (see Table 9-1) and Interface Modules (see Table 9-2).

TN-1X/S subrack codesEach TN-1X/S equipped subrack comprises an unequipped subrack (25G MU00 750 HHX) and the required complement of plug-in units (see Table 9-1) and Interface Modules (see Table 9-3).

Blank panel codesAll unused plug-in unit and Interface Module positions must be fitted with blank front panels. Codes for the relevant blank front panels are as follows:

1" Plug-in Unit Dummy Panel: 25R BN00 021 AAB

1.6" Plug-in Unit Dummy Panel: 25R BN00 021 AAC

1.8" Plug-in Unit Dummy Panel: 25R BN00 021 AAD

1" Interface Module Dummy Panel: 25R BN00 021 AAA

Service Interface Module Flexible Termination:25U JJ00 750 HJD

end of chapter

Table 9-3TN-1X/S Interface Module codes

Interface Modules Codes

75 Ω Traffic Access Module 25U JJ00 750 HHZ

120 Ω Traffic Access Module 25U JJ00 750 HJA

Flexible Termination Module 25U JJ00 750 HJD

Power & LCAP Module 25U JJ00 750 HJB

External Alarm Module 25U JJ00 750 HPF

Table 9-4Connector Panel codes

Connector Panel Code

75 Ω Connector Panel 25R PN00 021 AAF

120 Ω Connector Panel 25R PN00 021 AAG

EOW/CATT Connector Panel 25U EP00 750 HJC


10-1

10

Appendix A: Synchronous digital hierarchy 10-

The synchronous digital hierarchy, covered by ITU-T recommendations G.707, G.708, and G.709 (formally CCITT), details the international standards covering synchronous multiplexing and transmission.

• G.707 - Synchronous Digital Hierarchy Bit Rates

• G.708 - Network Node Interface for the Synchronous Digital Hierarchy

• G.709 - Synchronous Multiplexing Structure

Note: G.707, G708 and G.709 have been merged into a single standard, G.70X.

The standards propose a number of recommendations, including the transmission of Plesiochronous Digital Hierarchy (PDH) rates (except 8 Mbit/s). The tributary signals can be packaged into a standard sized container and located in an easily identifiable position within the multiplexed structure. The multiplexing structure includes provision for embedded network management channels.

The main advantages of the SDH are:

• Simplified multiplexing/demultiplexing techniques compared to PDH.

• Access to lower speed tributaries without the need to multiplex/demultiplex the entire high speed signal. This allows efficient drop and insert of channels and cross connect applications.

• Embedded network management channels which provide enhanced Operations, Administration, and Maintenance (OAM) capabilities, allowing efficiently controlled networks.

• Easy growth to higher multiplexing levels.

• Allows the transport of digital signals at the hierarchy bit rates specified in ITU-T recommendation G.702 (except 8 Mbit/s) and at broadband channel bit rates. This will allow SDH equipment to be introduced directly into existing networks and also allows the introduction of a wide range of services.

• The standard defines an optical interface which allows mid span fibre meets between equipment from different suppliers.


10-2 Appendix A: Synchronous digital hierarchy

SDH multiplexing structureThe first level of the SDH is at 155,520 kbit/s and is known as a Synchronous Transport Module 1 (STM-1) signal. Higher rates are integer multiples of the first level bit rate and are denoted by the corresponding multiplication factor of the first level rate. At present, the following rates constitute the synchronous digital hierarchy:

• STM-1: 155,520 kbit/s

• STM-4: 622,080 kbit/s

• STM-16: 2,488,320 kbit/s (2.4 Gbit/s)

The SDH allows for any of the current transmission rates (except 8 Mbit/s) to be mapped into containers, called Virtual Containers (VCs). The containers can be combined into standard formats in order to form the payload of the STM-1 signal. Different containers can be mixed, allowing for different rates to be carried simultaneously within the same structure.

The generalised multiplexing structure of the SDH is shown in Figure 10-1.

Figure 10-1SDH generalised multiplexing structure

The elements of the SDH are as follows:

Container (C-n), n=1 to 4This is the basic element of the STM signal consisting of a group of bytes allocated to carry the transmission rates defined in ITU-T recommendation G.702 (i.e. 1544 kbit/s and 2048 kbit/s transmission hierarchies).

Virtual Container (VC-n), n=1 to 4The lower order VC-ns (n=1 or 2) are built up of the basic container (C-n, n=1 or 2) plus additional capacity to carry Path Overhead (POH) information.

The higher order VC-ns (n=3 or 4) are built up of either a single basic container (C-n, n=3 or 4), or an assembly of Tributary Unit Groups (TUGs), together with the appropriate POH information.

STM-N AUG AU-4 VC-4

AU-3 VC-3

TUG-3

TUG-2

TU-3 VC-3

C-3

TU-2 VC-2 C-2

TU-12 VC-12 C-12

TU-11 VC-11 C-11

C-4 140 Mbit/s

45 Mbit/s34 Mbit/s

6 Mbit/s

2 Mbit/s

1.5 Mbit/s

x1

x3

xN

x1

x1

x3

x3

x4

x7

x7

PointerProcessing

Multiplexing

Aligning

Mapping


Appendix A: Synchronous digital hierarchy 10-3

10

The POH information includes VC path performance monitoring, signals for maintenance purposes, and alarm status indications. The POH information for the higher order VC-ns also includes multiplex structure indications which detail the VC composition.

Tributary Unit (TU-n), n=1 to 3This element consists of a VC plus a Tributary Unit pointer and provides adaptation between the lower order path layer and the higher order path layer. The pointer value indicates the phase alignment of the VC with respect to the TU POH added to it. The pointer location is fixed with respect to this higher level VC.

Tributary Unit Group (TUG-n), n=2 or 3This element is formed by a group of identical TUs or TUGs, allowing mixed capacity payloads to be constructed.

Administrative Unit (AU-n), n=3 or 4This element consists of a VC-n (n=3 or 4) plus an AU pointer and provides adaptation between the higher order paths and the multiplex section layer. The pointer value indicates the phase alignment of the VC-n with respect to the STM-1 frame. The location of the pointer is fixed within the STM-1 frame structure.

Administrative Unit Group (AUG)This element is formed by a group of byte interleaved AUs. The AUG has a fixed position in the STM payload.

Synchronous Transport Module Level 1 (STM-1)This is the basic element of the SDH and comprises a single AUG and the Section Overhead (SOH) information. The STM-1 frame structure comprises an array of 270 columns by 9 rows of 8-bit bytes as shown in Figure 10-2.

The frame length is 125 µs. The order of transmission is from left to right, then from top to bottom. Within each byte, the most significant bit (bit 1) is transmitted first. The SOH information includes STM-1 framing, section performance monitoring, and other maintenance and operational information.



Figure 10-2STM-1 frame structure

Synchronous Transport Module Level N (STM-N)This element defines the Nth level of the SDH. An STM-N contains N AUGs together with SOH information. The N AUGs are one-byte interleaved and have a fixed phase relationship with respect to the STM-N.

Nortel TN-1XThe Nortel TN-1X uses a subset of the SDH multiplexing structure as shown in Figure 10-3.

Figure 10-3Nortel TN-1X - multiplexing structure

The procedure for assembling the STM-1 frame for the Nortel TN-1X and brief descriptions of the overhead bytes are given in the following sections.

Mapping of a 2048 kbit/s signal into a VC-12The 2048 kbit/s tributary signal (C-12) is asynchronously mapped into a VC-12 signal (see Figure 10-4).

The additional fixed stuff bits and bytes maintain a defined size of 140 bytes for a 500 µs TU multiframe (i.e. 4 STM-1 frames). Asynchronous mapping allows for justification of the tributary, allowing for variations between the tributary clock rates and the clock providing the timing for the synchronous network. The VC-12 signal contains a POH byte, which provides error checking, signal label, and path status information for the VC-12 path (see “Path overheads” on page 10-10).

SOH

SOH

AU PTRs STM-1Payload

270 Columns (Bytes)

9 Rows

1 9 10 270

1

3

9

4

5

STM-N AUG AU-4 VC-4 TUG-3 TUG-2 TU-12 VC-12 C-12 2 Mbit/sx1xN x3 x7 x3

x1TU-3 VC-3 C-3 34 Mbit/s



10

Figure 10-42048 kbit/s tributary/VC-12/TU-12 mapping

Mapping of a 34368 kbit/s signal into a VC-3 The 34368 kbit/s tributary signal (C-3) is asynchronously mapped into a VC-3 signal (refer to Figure 10-5).

In addition to the VC-3 POH, the VC-3 consists of a payload of 9 x 84 bytes every 125 µs. This payload is divided into three subframes, each subframe comprising information bits (I), two sets of justification control bits (C1, C2), two justification opportunity bits (S1, S2), and fixed stuff bits (R).

V5

R

R

J2

R

Z6

R

Z7

R

32 Bytes

32 Bytes

32 Bytes

31 Bytes

C1 C2 O O O O R R

C1 C2 O O O O R R

C1 C2 O O O O R S1

S2 I I I I I I I

Asynchronous mappingfor 2048 kbit/s tributary

(Multiframe)

140

Byt

es

500

µs

V1 (Ptr 1)

V2 (Ptr 2)

V3 (Ptr 3, Action)

V4 (Reserved)

V5

State ofH4 byte

XXXXXX00

XXXXXX01

XXXXXX10

XXXXXX11

144

Byt

es

Zero Ptroffset

I: Information BitC: Justification ControlR: Fixed StuffJ2: LO Path Trace

O: OverheadS: Justification OpportunityV5:VC1 Path OverheadZ6, Z7: Reserved

VC-12 TU-12



Figure 10-534368 kbit/s tributary/VC-3 mapping

Multiplexing of VC-12s into a TUG-2A pointer is added to the VC-12 signal to form a TU-12, the pointer indicates the phase alignment of the VC-12 with respect to the TU-12 (see Figure 10-4). If the timing of a VC causes it to slip with respect to the timing of the TUG, the pointer is adjusted to indicate the new alignment. Each TU-12 occupies four columns. Figure 10-6 shows a conceptual view of the mapping of three TU-12s into a TUG-2. In practice, the columns of each TU-12 are interleaved as shown in Figure 10-7.

VC-3 POH

3 rows

3 rows

3 rows

841

3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x813x81 3x81 3x81 3x81 3x81 3x81CC

3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x813x81 3x81 3x81 3x81 3x81 3x81CC

3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x81 3x813x81 3x81 3x81 3x81 3x81 C 81A B

= RRRRRRRR

R Fixed stuff bitStuff control bitJustification opportunities bitInformation bit

C1,C2S1,S2I

RRRRRRC1C2 RRRRRRRS1 S2I I I I I I I

J1

B3C2

G1

F2

H4

Z3

K3

Z5

T1

T2

T3

125 µs



10

Figure 10-6Multiplexing of TU-12 via a TUG-2

Figure 10-7TU-12/TUG-2/TUG-3 multiplexing

VCPtr

VCPtr

VCPtr

4 Columns

TU-129 Rows

TUG-212 Columns

1 2 3 4 5 6 7

1 2 3 4 5 6 7

1 2 3 4 5 6 7

1 2 3 4 5 6 7

1 2 3 4 5 6 7

1 2 3 4 5 6 7

CB

CBACBC

ABACBA

A

TU-12

TUG-2

TUG-3

(1) (2) (3) (7)

3Stuffing

12 4

56

78

9

1 2 3 4 5 6 7

858684



Multiplexing of TUG-2s into a TUG-3The mapping of TUG-2s into a TUG-3 is a fixed mapping as shown in Figure 10-7. The inclusion of the TUG-3 is primarily to provide a structure for 34,368 kbit/s and 44,736 kbit/s transmission rates.

Multiplexing of a VC-3 into a TUG-3A pointer is added to the VC-3 signal to form a TU-3, the pointer indicates the phase alignment with respect to the TU-3 frame. The individual TU-3 pointers are contained within the H1, H2, and H3 bytes within the TUG-3, see Figure 10-8.

Figure 10-8Multiplexing of a TU-3 via a TUG-3

Mapping of TUG-3s into a VC-4The mapping of three TUG-3s into a VC-4 is fixed as shown in Figure 10-9. Column one of the VC-4 contains the nine POH bytes, which provide error checking, signal label, path status, and multiplexing structure information for the VC-4 path (see “Path overheads” on page 10-10). Columns two and three are fixed stuff.

Fix

ed s

tuff

TUG-3

VC-3

Container-3

J1

B3

C2

F2

H4

N1

K3

Z5

VC-3 POH

G1

H1

H2

H3

86 columns

85 columns



10

Figure 10-9Multiplexing of three TUG-3s into a VC-4

Mapping of a VC-4 into a STM-1 via an AU-4/AUGAn AU pointer is added to the VC-4 to form an AU-4, the pointer indicates the phase alignment of the VC-4 with respect to the STM-1 frame. The AU-4 pointers are in a fixed location in the STM-1 frame (see Figure 10-10). The AU-4 is placed directly in the AUG, which together with the SOH, forms the STM-1.

Figure 10-10Mapping of a VC-4 into a STM-1 via an AU-4/AUG

The Section Overhead (SOH) provides STM-1 framing, section performance monitoring and other maintenance functions pertaining to the section path (see “Section overhead” on page 10-11).

ABCA BC

ABCABC

TUG-3

VC-4

312 4

56

78

9

ABC

261

POH

1 1 186 86 86

TUG-3(A)

TUG-3(B)

TUG-3(C)

1

2619

AU-4AUG

SOH

SOH

5

3

AU-4 PTR

VC-4

J1

B3

C2

F2

H4

N1

Z4

Z5VC-4 POH

G1



Path overheadsThe Path Overhead (POH) forms part of the relevant Virtual Container and provides information for use in the end-to-end management of a synchronous path.

The V5 byte in the VC-12 (see Figure 10-4) is the path overhead information pertaining to the VC-12 end-to-end path. The function of the V5 bits is shown in Figure 10-11 and is detailed in subsequent paragraphs:Figure 10-11VC-12 Path Overhead

• BIP-2 (Bits 1 and 2). The Bit Interleaved Parity (BIP) bits are used to provide an error monitoring function for the VC-12 path.

• REI (Bit 3). The Remote Error Indication (REI) bit is used to communicate detected BIP-2 errors back to the VC-12 path originator.

• RFI (Bit 4). Remote Fail Indicator (RFI). Not used in present applications.

• Signal label (Bits 5 to 7). These bits are used to indicate the payload mapping and equipped status.

• RDI (Bit 8). The Remote Defect Indicator (RDI) bit is used to indicate certain detected TU path alarms to the VC-12 path originator.

The VC-3/VC-4 path overhead consists of nine bytes as shown in Figure 10-8 and Figure 10-10. The function of the nine bytes is as follows:

• Path trace (J1). This byte is used to provide a fixed length string which is transmitted repetitively so that the receiving terminal can verify connection to the intended transmitter.

• Path BIP-8 (B3). This byte provides an error monitoring function for the VC-3/VC-4 path.

• Signal label (C2). This byte is used to indicate the composition of the VC-3/VC-4 payloads.

• Path status (G1). This byte is used to convey path terminating status and performance information back to the VC-3/VC-4 path originator.

• Path user channel (F2). This byte is available for user communication purposes between path elements. Not used in present applications.

• Multiframe indicator (H4). This byte provides a generalised multiframe indicator for payloads.

• Automatic Protection Switching (APS) (K3). This byte is allocated for APS signalling for high order path protection. Not used in present applications.

• Spare (N1, Z4, Z5). Not used in present applications.

1

BIP-2 Signal Label

REI RFI RDI

2 3 4 5 6 7 8



10

Section overheadThe Section Overhead (SOH) forms part of the STM-1 frame. The SOH is divided into two parts, the Multiplexer Section Overhead (MSOH) and the Regenerator Section Overhead (RSOH). The MSOH is only generated/terminated at each end of a multiplex section (i.e. where an STM is assembled/disassembled) and passes transparently through regenerators. The RSOH is assembled/terminated at each regenerator and at the end of a multiplex section. The section overhead bytes are detailed in Figure 10-12.

Figure 10-12Section overhead

The function of the RSOH bytes is as follows:

• Framing (A1, A2). These bytes are used for frame alignment purposes.

• BIP-8 (B1). This byte is used to provide an error monitoring function for a regenerator section. The byte is also used in the frame alignment process.

• Order wire (E1). This byte is used to provide an order wire channel which may be accessed at regenerators and multiplexers.

• User channel (F1). This byte is reserved for user purposes. Not used in present systems.

• DCCR (D1 to D3). The Data Communication Channel (DCC) bytes provide a 192 kbit/s regenerator data channel. These bytes can be used as a physical layer for the ECC.

• Regenerator Section Trace (J0). Not used in present applications.

The function of the MSOH bytes is as follows:

• BIP-24 (B2). These bytes are used to provide an error monitoring function for the multiplex section.

D12D11D10

F3S1 F3 K3 K3 M1 E2

D7

D4

B2 B2 B2 K1

D5

D8 D9

D6

K2

H1 H1 H1 H2 H2 H2 H3 H3 H3

D3

F1

J0A2A2A2A1A1A1

B1

D1 D2

E1

A1, A2:B1, B2:J0:

D1 - D12:E1, E2:F1:H1, H2, H3:K1, K2:S1

F3, K3:M1:

FramingBit Error MonitoringRegenerator Section Trace - not currently usedData ChannelOrder WireUser ChannelAU-Pointer BytesAutomatic Protection SwitchingTiming Marker Byte - not currently usedSpareSection FEBE - not currently used

Bytes reserved for national use.All unmarked bytes are reserved for future international standardisation.

RSOH

AU-Pointer

MSOH



• APS channel (K1, K2). The Automatic Protection Switching (APS) Channel bytes are used for APS signalling. In present systems, the bytes are only used to communicate multiplex section REI and Alarm Indication Signal (AIS) indications to the far multiplexer.

• DCCM (D4 to D12). The Data Communication Channel bytes provide a 576 kbit/s multiplex data channel. These bytes can be used as a physical layer for the ECC.

• Order wire (E2). This byte is used to provide an order wire channel which may be accessed only at multiplex section terminations.

• Synchronisation Status Messaging Byte (S1). This byte is used for transmitting synchronisation status.

• Spare (F3, K3). Function not allocated. Not used in present applications.

• Section REI (M1). Not used in present applications.

All other bytes in the RSOH and MSOH are either reserved for national use or for future international standardisation and are not used in present systems.

Nortel TN-1X/4Multiplexing structureThe TN-1X/4 multiplexer provides interfaces at the STM-4 level of the Synchronous Digital Hierarchy. The STM-4 signal contains four AUGs together with Section Overhead (SOH) information (see Figure 10-13). The four AUGs are one-byte interleaved and have a fixed phase relationship with respect to the STM-4.

Figure 10-13STM-4 frame structure

Each AUG has a structure of 9 rows by 261 columns plus 9 bytes in row 4 (for the AU pointers). In this document, the AUGs (and corresponding STM-1s) are denoted #1, #2, #3 and #4 corresponding to their order in the STM-4 payload.

1 9

AUG

1 261

#1 #2 #3 #4

SOH12341234

4 x 9 4 x 261STM-4

1 9

AUG

1 261

1 9

AUG

1 261

1 9

AUG

1 261

12341234

SOH



10

The section overhead bytes occupy columns 1 to 36, rows 1 to 3 and 5 to 9 of the frame as shown in Figure 10-14. It should be noted that the TN-1X/4 multiplexer assembles the STM-4 signal by interleaving four STM-1 signals, each of which has a SOH. Therefore the STM-4 frame contains STM-1 overhead in all four STM-1 channels and some of the bytes reserved for national and future international usage contain STM-1 overhead bytes. In the receive direction, only the appropriate SOH bytes are processed. The first row of the section overhead (i.e. 36 columns) is not scrambled.

Figure 10-14STM-4 section overhead

end of chapter

C1A1A1 A1 A1 A1 A1 A1 A1 A1 A1A1 A1 A2 A2 A2 A2 A2 A2 A2 A2 A2 A2 A2 A2 C1 C1 C1

F1 F1 F1 F1

D3 D3 D3 D3

K2 K2

D9

D11 D11D11 D11

D7 D7 D7 D7

D10 D10 D10D10

TN-1X/4 overhead

ITU-U defined overhead

A1A1 A1 A1 A1 A1 A1 A1 A1 A1

36 columns

AU Pointers

AU Pointers

9 ro

ws

9 ro

ws

36 columns

B1

E2

K2

D12

K1

D6

D9

D5

D8

D11

D4

D7

D10

M1F3S

B2

Z0

F1

D3

J0

E1

D2

B1

D1

A2A1

Bytes reserved for national use.All unmarked bytes are reserved for future use international standardisation (for media dependent, additional national use and other purposes).

A1 A2 A2 A2 A2 A2 A2 A2 A2 A2 A2 A2

B2 B2 B2 B2 B2 B2 B2 B2 B2 B2 B2

F3 F3 F3 F3 F3 F3 F3 F3 F3 F3 K3 K3 K3 K3 K3 K3 K3 K3 k3 K3 K3

Z0Z0

B1 B1 B1

D1 D1 D1 D1

E1 E1 E1 E1

D2 D2 D2

B2 B2 B2 B2 B2 B2 B2 B2 B2 B2 B2 B2

D4 D4 D4 D4

F3F3 F3 F3F3 F3 F3 F3 F3 F3 F3 F3 K3 K3 K3 K3 K3 K3 K3 K3 K3 K3 K3 K3

D8 D8 D8 D8

D5 D5 D5 D5

K1 K1 K1 K1 K2 K2

D6 D6 D6 D6

D9 D9 D9

D12 D12D12 D12

E2 E2 E2 E2


11-1

11

Important notes 11-Introduction

This appendix provides operational qualifications for the Nortel TN-1X Release 7.

A user who is uncertain of the operation of the system should refer to the relevant section of the NTPs, where explanatory notes are provided.

If any assistance is required on the Nortel TN-1X or its Element Controller, the Customer Service Desk* 24 hour help line should be contacted on one of the following numbers:

• UK Calls

— Free Phone: 0800 626 881

— Telephone:0181 361 4693

— Fax:0181 945 3456

• International Calls

— Telephone:44 181 361 4693

— Fax:44 181 945 3456

Note: * Access to assistance from the Customer Service Desk 24 hour help line is subject to a suitable Support Agreement being in place.

Operational qualifications for Release 7 TN-1X multiplexer1 Payload Manager switching should not be performed unless absolutely

operationally necessary. Switching between Payload Managers should be preferably only be performed during periods of low traffic density.

2 As a result of hot inserting an Aggregate Unit of a gateway multiplexer, communications loss to the NE may occur:

— Qecc communication failures may occur for up to 60 seconds on the other aggregate and on the STM-1 tributaries.

— Communication failures may be reported on the Element Controller for up to 15 seconds.

3 Loopbacks on 2 Mbit/s Tributary Unit variants 25U JU00 750 HVQ/HVT work correctly except for the alarms that are reported when the loopbacks are applied. For example, if a 2 Mbit/s tributary connection is made and


11-2 Important notes

there is no traffic input, a ‘PPI-LOS’ alarm is reported as expected. When a ‘Local’ loopback is applied to that tributary port, the ‘PPI-LOS’ alarm should clear. However, when using these variants of the 2 Mbit/s Tributary Unit’ the alarm does not clear but traffic is restored. Conversely, whenever there is no connection associated with a tributary port and a ‘Local’ loopback is applied to that port, ‘PPI-Unexp_Signal’ and ‘PPI-AIS’ would be expected to be reported. However, when using these variants of the 2 Mbit/s Tributary Unit’, the alarms are not reported.

4 The user must ensure that the correct Payload Manager and Aggregate Units are configured on the NE before imposing configuration. Failure to do so will result in loss of communications to the NE once the defaults have been imposed. A site visit will be required to correct this situation.

end of chapter


12-1

Index 12-

12

120 Ω Traffic Access Module (N+1 Protection) (TN-1X) 8-13

120 Ω Traffic Access Module (TN-1X) 8-10120 Ω Connector Panel 8-412 Mbit/s Tributary Unit 4-9

N+1 protection 3-1334 Mbit/s Tributary Unit 4-975 Ω Star Card 8-2875 Ω Traffic Access Module (N+1 Protection)

(TN-1X) 8-675 Ω Traffic Access Module (TN-1X) 8-475 Ω Traffic Access Module (TN-1X/S) 8-875 Ω Connector Panel 8-40

Aalarms

external 5-6, 7-6filtering 5-5handling 5-5masking 5-5monitoring 2-4, 5-5rack 5-5

automatic laser shutdown 3-20laser test facility 3-22

Bbackplane

connectors 3-25links 3-29TN-1X 3-26TN-1X/S 3-28

blank panel 3-32codes 9-3

Ccabling

TN-1X subrack 8-45TN-1X/S subrack 8-45

card controllers 5-3categories

rack alarm 5-5channel

designations 2-13channel numbering schemes 2-13coding 9-1configuration 2-4configuration data 5-19configuration tables 5-16

status 5-19connections 2-16

internal traffic 2-17traffic 2-18

connectivity 2-13connector panels 3-10

120 Ω Connector Panel 8-4175 Ω Connector Panel 8-40EOW/CATT Connector Panel 8-43TN-1X codes 9-3

construction 3-23equipment practice 7-1Interface Modules 3-29plug-in units 3-29

cover 3-30

Ddefragmentation 2-17dimensions 7-1drop and insert multiplexer 2-7

chains 2-8ring 2-9

Eearthing 3-32ECC port 5-24electro static discharge 3-31electromagnetic compatibility 3-31, 7-7Element Controller 2-4


12-2 Index

standby 2-4Engineering Order Wire 2-20

operation 3-23environmental conditions 7-7EOW, see Engineering Order WireEOW/CATT Connector Panel 8-43equipment codes 9-1equipment management 5-1

bus architecture 5-2equipment practice 7-1events

monitoring 2-4External Alarm Module 8-38external alarms 5-6, 7-6external connections 8-1external interfaces, see system interfaces

FFlexible Access Module 8-31Flexible Access Module (External

Alarms) 8-36Flexible Termination Module 8-30frame structure

STM-1 10-4STM-4 10-12

HHigh Speed Aggregate Module 8-21High Speed Traffic Access Module 8-19High Speed Tributary Module 8-23

IInterface Modules 3-8, 3-29

120 Ω Traffic Access Module (N+1 Protection) (TN-1X) 8-13

120 Ω Traffic Access Module (TN-1X) 8-10

75 Ω Star Card 8-2875 Ω Traffic Access Module (N+1

Protection) (TN-1X) 8-675 Ω Traffic Access Module (TN-1X) 8-475 Ω Traffic Access Module

(TN-1X/S) 8-8dimensions 7-2External Alarm Module 8-38Flexible Access Module 8-31Flexible Access Module (External

Alarms) 8-36Flexible Termination Module 8-30

High Speed Aggregate Module 8-21High Speed Traffic Access Module 8-19High Speed Tributary Module 8-23Power & LCAP Module 8-33Station Service Module 8-25TN-1X codes 9-2TN-1X/S codes 9-3

interfacessee also system interfacessee internal traffic interfacessee system interfaces

internal traffic interfaces 4-1overhead buses 4-4Payload Manager/Aggregate Unit 4-3Tributary Unit/Payload Manager 4-2

inventory 5-21

LLAN transceivers 8-50LCAP, see Local Craft Access PanelLocal Craft Access Panel 3-10, 8-2local terminal 5-21loopback 3-16

2 Mbit/s Tributary Unit 3-1734 Mbit/s Tributary Unit 3-18STM-1 Aggregate Unit 3-18STM-1 Tributary Unit 3-18

MManual Area Addresses 5-24mapping

2 Mbit/s to VC-12 10-4TUG-3s to VC-4 10-8VC-4 to STM-1 10-9

masking 5-5multiplexing

TUG-2s to TUG-3 10-8VC-12s to TUG-2 10-6

NN+1 2 Mbit/s tributary protection 3-13network

management 5-22Network Resource Manager 2-5Nortel

SDH transmission equipment 1-2Nortel TN-1X 2-1

block diagram 3-2equipment codes 9-1


Index 12-3

12

external interfaces 2-2multiplexing structure 10-4subrack layout 3-4traffic processing 4-5, 4-6

Nortel TN-1X/4multiplexing structure 10-12STM-1 routing 2-10traffic processing 4-7typical deployment 2-11

Nortel TN-1X/Sblock diagram 3-3external interfaces 2-2subrack layout 3-5

Ooperating parameters 7-1

Ppath overhead 10-10path protection switching 3-11path trace 5-13Payload Manager 4-12

switching 3-15performance logs

24 hour reports 5-13UAT logs 5-13

performance monitoring 2-4, 5-8plug-in units 3-5, 3-29

codes 9-1dimensions 7-2TN-1X subrack 3-7TN-1X/S subrack 3-8

portdesignations 2-13

power 6-1input supply 7-1power consumption 7-1TN-1X subrack 6-1TN-1X/S subrack 6-2

Power & LCAP Module 8-33Power Unit 6-1protection 3-13

path 3-11Payload Manager 3-15

Rrack alarm categories 5-5real time clock 5-4remote layer management 5-24

reporting 2-4rings, see drop and insert multiplexerrouters 5-26

SSDH, see synchronous digital hierarchysection overhead 10-11, 10-13security management 2-4Service Interface Module (SIM), see Interface

ModulesSIA cover 3-30signal fibre working 5-14signal label 5-14single fibre working 3-18, 3-19software 5-15

status 5-17upgrade 5-18

standby Element Controller 2-4Station Service Module 8-25status

configuration tables 5-19software 5-17

STM-1frame structure 10-4section overhead 10-11tributaries 2-11

STM-1 Aggregate Unit 4-13STM-1 Tributary Unit 4-10STM-4

aggregates 2-9frame structure 10-12section overhead 10-13

STM-4 Optical Aggregate Unit 4-14subrack

backplane 3-25TN-1X 3-1TN-1X dimensions 7-1TN-1X layout 3-4TN-1X/S 3-1TN-1X/S dimensions 7-2TN-1X/S layout 3-5weight 7-2

Subrack Controller 5-3switching

path protection 3-11Payload Manager 3-15synchronisation 6-6

synchronisation 6-4alarms 6-14source hierarchy 6-5


12-4 Index

sources 6-4switching 6-6

synchronisation source messaging 6-6synchronous digital hierarchy 1-1, 10-1

administrative unit 10-3administrative unit group 10-3container 10-2multiplexing structure 10-2STM-1 10-3STM-N 10-4transport equipment 1-3tributary unit 10-3tributary unit group 10-3virtual container 10-2

system configurations 2-5drop and insert multiplexer 2-7STM-1 tributaries 2-11STM-4 aggregates 2-9terminal multiplexer 2-7

system interfaces2 Mbit/s traffic 7-334 Mbit/s traffic 7-3Engineering Order Wire 7-7external alarms 7-6external synchronisation 7-6local terminal 7-6network management 7-6rack alarm bus 7-6STM-1 electrical aggregate 7-5STM-1 electrical tributary 7-5STM-1 optical aggregate (long haul) 7-3STM-1 optical aggregate (short haul) 7-4STM-1 optical tributary (long haul) 7-3STM-1 optical tributary (short haul) 7-4STM-4 optical aggregate (intra-office

1310 nm) 7-5STM-4 optical aggregate (long haul

1310 nm) 7-5STM-4 optical aggregate (long haul

1550 nm) 7-6

Tterminal multiplexer 2-7thermal qualifications 3-32third-party routers 5-26traffic

connections 2-16, 2-18internal connections 2-17user labels 2-20

Traffic Interface Module (TIM), see Interface Modules

traffic processing 4-4TN-1X 4-5, 4-6TN-1X/4 4-7

UUAT logs 5-13unit duplication

Payload Managers 3-15upgrade

software 5-18user labels 2-20

Vvariants 3-3VC-12 path overhead 10-10VC12/TU12 protection switching 3-11VC-4 path overhead 10-10

Wweight 7-2


International Broadband Networks (Dept18600)Nortel plcOakleigh Road SouthLondon, N11 1HB

So far as Northern Telecom is aware the contents of this document are correct. However, such contents have been obtained from a variety of sources and Northern Telecom can give no warranty or undertaking and make no representation as to their accuracy. In particular, Northern Telecom hereby expressly excludes liability for any form of consequential, indirect or special loss, and loss of data, loss of profits or loss of business opportunity, howsoever arising and whether sustained by the user of the information herein or any third party arising out of the contents of this document.

SDH TRANSMISSION


Copyright 1995, 1996, 1997 Northern Telecom

The copyright of this document is the property of Northern Telecom. Without the written consent of Northern Telecom, given by contract or otherwise, this document must not be copied, reprinted or reproduced in any material form, either wholly or in part, and the contents of this document, or any methods or techniques available therefrom, must not be disclosed to any other person whatsoever.

NORTHERN TELECOM CONFIDENTIAL: The information contained in this document is the property of Northern Telecom. Except as specifically authorized in writing by Northern Telecom, the holder of this document shall protect same in whole or in part from disclosure and dissemination to third parties and use same for evaluation, operation, and maintenance purposes only.

Document Number: 323-1061-100Product Release Number: Release 7Document Status: Standard (Revision 1)Date: November 1997Printed in England

TN-1X

Documents

expressly

germanium

optimum eye

p3 strap p2

p6 leave p5

p6 strap p3

continuous

excluding