Cables, connections and ports

CABLES, CONNECTIONS

AND PORTS

CABLES

1. Patch Cables

A patch cable or patch cord or patch lead is

an electrical or optical cable used to

connect ("patch-in") one electronic or

optical device to another for signal routing.

Patch cables are typically CAT5 / CAT5e Ethernet cables

linking a computer to a nearby network hub, switch or router.

Normally manufactured using stranded rather than solid

sheathing in order to give them pliability that reduces risk of

breakage when unplugging or carrying them.

…Continued (Patch Cables)

Size Can be as short as 3 inches (ca. 8 cm), to connect

stacked components or route signals through a patch

bay, or as long as twenty feet (ca. 6 m) or more in

length for snake cables.

As length increases, the cables are usually thicker

and/or made with more shielding, to prevent signal loss

(attenuation) and the introduction of unwanted radio

frequencies and hum (electromagnetic interference).

…Continued (Patch Cables)

Data Transmission Speed

Cat 5 cables are the most basic type and provide

speeds of either 10 Mbps or 100 Mbps.

Cat 5e, which means Cat 5 Enhanced, allows for faster

data transmission than its predecessor. It caps at 1,000

Mbps.

Cat 6 is the latest and offers the best performance of

the three. It’s capable of supporting 10 Gbps speeds.

2. Ethernet Crossover Cables

An Ethernet crossover cable is a type of

Ethernet cable used to connect

computing devices together directly.

Commonly used when temporarily networking two devices

in situations where a network router, switch or hub is not

present.

Ethernet crossover cables should only be used for direct

network connections. In particular, attempting to connect a

computer to a hub with a crossover cable will prevent that

network link from functioning.

3. USB Cables

A universal serial bus (USB) cable connects

between a computer and a peripheral device

such as a printer, monitor, scanner, mouse or keyboard.

USB was designed to standardize the connection of

computer peripherals to personal computers, both to

communicate and to supply electric power.

Three basic kinds or sizes of USB connectors:

The older "standard" size, in its USB 1.1/2.0 and USB 3.0

variants (for example, on USB flash drives).

The "mini" size (primarily for the B connector end, such as

on many cameras).

the "micro" size, in its USB 1.1/2.0 and USB 3.0 variants (for

example, on most modern cellphones).

…Continued (USB Cables)

Each end of a USB cable uses a different kind of

connector; an A-type or a B-type.

This kind of design was chosen to prevent electrical

overloads and damaged equipment, as only the A-

type socket provides power.

In common practice, the A-type connector is usually

the full size, and the B-type side can vary as needed.

The data cables for USB 1.x and USB 2.x use a twisted

pair to reduce noise and crosstalk. USB 3.0 cables

contain twice as many wires as USB 2.x to support

SuperSpeed data transmission, and are thus larger in

diameter.

… Continued (USB Cables)

The USB 1.1 standard specifies that a standard cable

can have a maximum length of 5 meters with devices

operating at Full Speed (12 Mbit/s), and a maximum

length of 3 meters with devices operating at Low

Speed (1.5 Mbit/s).

The USB 3.0 standard does not directly specify a

maximum cable length, requiring only that all cables

meet an electrical specification: for copper cabling

with AWG 26 wires the maximum practical length is 3

meters (9.8 ft).

… Continued (USB Cables)

Data Transfer Speed USB 1.0/1.1 can transmit data at speeds up to 12

Mbps.

USB 2.0 can transmit data at speeds up to 480 Mbps

and is compatible with older versions of USB.

USB 3.0 can transmit data at speeds up to 4.8 Gbps.

It is compatible with previous versions of USB.

4. Twisted Pair Cables

Twisted pair cabling is a type of wiring in which two

conductors of a single circuit are twisted together for

the purposes of canceling out electromagnetic

interference (EMI) from external sources.

The tighter the twisting, the higher the supported

transmission rate and the greater

the cost per foot.

Two types of Twisted Pair Cables:

Unshielded Twisted Pair (UTP Cable)

Shielded Twisted Pair(STP Cable)

Advantages :-

It is a thin, flexible cable that is easy to

string between walls.

More lines can be run through the same

wiring ducts.

Electrical noise going into or coming

from the cable can be prevented.

Cross-talk is minimized.

Disadvantages :-

Usually have stringent requirements for

maximum pulling tension as well as minimum

bend radius.

In video applications that send information

across multiple parallel signal wires, twisted

pair cabling can introduce signaling delays

known as skew which cause subtle color

defects and ghosting due to the image

components not aligning correctly when

recombined in the display device.

A) UTP Cables

UTP cables are found in many Ethernet networks

and telephone systems.

The cables are typically made with copper wires

measured at 22 or 24 American Wire Gauge (AWG),

with the colored insulation typically made from an

insulator such as polyethylene or FEP and the total

package covered in a polyethylene jacket.

Most common cable used in computer networking.

Modern Ethernet, the most common data networking

standard, can use UTP cables.

UTP is also finding increasing use in video applications,

primarily in security cameras.

B) STP Cables

Shielded to prevent electromagnetic

interference.

There is a foil or braid shield

inside the jacket covering all

wires (as a group).

There is a shield around each individual pair, as well as

around the entire

group of wires (referred to as double shield twisted pair).

… Continued (STP Cables)

ISO/IEC 11801:2002 (Annex E) attempts to

internationally standardise the various

designations for shielded cables by using combinations

of three letters - U for unshielded, S for braided shielding,

and F for foiled shielding - to explicitly indicate the type

of screen for overall cable protection and for individual

pairs or quads, using a two-part abbreviation in the form

of xx/xTP.

When shielding is applied to the collection of pairs, this is

usually referred to as screening.


Common shielded cable types used

by Cat. 6a, Cat.7 and Cat.8 cables include:

Shielded twisted pair (U/FTP):Also pair in metal foil. Individual shielding with foil for

each twisted pair or quad. This type of shielding

protects cable from external EMI entering or exiting

the cable and also protects neighboring pairs from

crosstalk.


Screened twisted pair (F/UTP, S/UTP

and SF/UTP):Also foiled twisted pair for F/UTP. Overall foil, braided

shield or braiding with foil across all of the pairs within

the 100 Ohm twisted pair cable. This type of shielding

protects EMI from entering or exiting the cable.


Screened shielded twisted pair (F/FTP and

S/FTP):Also fully shielded twisted pair, shielded screened

twisted pair, screened foiled twisted pair, shielded foiled

twisted pair. Individual shielding using foil between the

twisted pair sets, and also an outer metal and/or foil

shielding within the 100 Ohm twisted pair cable. This

type of shielding protects EMI from entering or exiting

the cable and also protects neighboring pairs from

crosstalk.

5. Coaxial Cables

Coaxial cable, or coax, is a type of cable

that has an inner conductor surrounded

by a tubular insulating layer, surrounded

by a tubular conducting shield.

Difficult to install.

Highly resistant to signal interference.

It can support greater cable lengths between network

devices than twisted pair cable.

A. Outer plastic sheath

B. Woven copper shield

C. Inner dielectric insulator

D. Copper core

… Continued (Coaxial Cables) Uses: Short coaxial cables are commonly

used to connect home video equipment, in

ham radio setups, and in measurement

electronics.

Micro coaxial cables are used in a range of

consumer devices, military equipment, and also in ultra-

sound scanning equipment.

Coax cable is often used to carry data/signals from an

antenna to a receiver—from a satellite dish to a satellite

receiver, from a television antenna to a television receiver,

from a radio mast to a radio receiver, etc.

6. Fibre Optic Cables

Uses glass (or plastic) threads (fibers) to

transmit data.

Transmits light rather than electronic signals eliminating the

problem of electrical interference.

Ideal for environments that contain a large amount of

electrical interference.

Ability to transmit signals over much longer distances

than coaxial and twisted pair.

Capability to carry information at vastly greater

speeds.

Effective for the services like video conferencing and

interactive services where fast speed is required.

… Continued (Fibre Optic Cables) Capacity: In September 2012, NTT Japan demonstrated

a single fiber cable that was able to transfer

1 petabit per second (1015bits/s) over a distance of 50

kilometers.

Modern fiber cables can contain up to a thousand fibers in a

single cable, with potential bandwidth in the terabytes per

second.

Reliability: Optical fibers are very strong, but the

strength is drastically reduced by

unavoidable microscopic surface flaws

inherent in the manufacturing process.

7. VGA (Video Graphics Array)

Created way back in the 1980’s, the VGA

connection cable was the standard cable used to

connect a computer to a monitor.

VGA connections can be identified by 15 pins

arranged in 3 rows with 5 on each row. Each row

corresponds to the 3 different color channels used in

display: red, green, and blue.

More recently, it has faded out of popularity due to

the gradual shift towards digital connections over

analog.

8. DVI (Digital Visual Interface)The DVI connection became the

successor to VGA as technology

moved away from analog towards digital.

DVI connectors come in 3 varieties. DVI-A can transmit analog signals, allowing it to be

backwards compatible with VGA (useful for CRT monitors and

LCDs of lower quality).

DVI-D can transmit the newer digital signals.

DVI-I is capable of both analog and digital.

9. HDMI (High Definition

Multimedia Interface) Unlike VGA and DVI, HDMI sends both video

and audio signals together. The signals are digital only; thus,

HDMI is only compatible with newer.

HDMI connectors come in 4 types:

Type A is the most popular. This connector can be identified

by its 19 pins on the male head. Type A is compatible with

single-link DVI-D connections.

Type B is larger than Type A, coming in at 29 pins on the male

head. Type B is compatible with dual-link DVI-D connections.

Type C is a 19-pin connector that’s most often used with

portable devices, like camcorders and digital cameras.

Type D looks similar to a micro-USB cord. It also has 19 pins.

10. IDE (Integrated Drive Electronics)

IDE cables were used to connect

storage devices to a motherboard.

It’s the wide cable that looks like a ribbon with

more than 2 plugs.

The connectors on an IDE cable have 40 pins; the

smaller 2.5” drive variety uses a form-factor

version of the IDE that has 44 pins.

11. SATA (Serial Advanced

Technology Attachment)

Newer hard drives will likely use SATA ports over IDE

ports.

SATA was designed to succeed IDE, and it has.

Compared to IDE, SATA provides higher data

transfer speeds

A standard SATA cable can be identified by two

connectors, each having 7 pins and an empty

notch. It looks like a subtle L-shape.

12. eSATA (External Serial Advanced

Technology Attachment)

eSATA is not much different

from SATA, but it allows connections to devices

like external hard drives and optical drives.

This is useful because eSATA offers speeds much

faster than most FireWire and USB alternatives.

13. FireWire

The purpose of FireWire is

similar to that of USB: high speed data transfer for

computer peripherals.

FireWire is not as widespread as USB.

FireWire cables come in two forms: 1394a (which

has a transfer speed of 400 Mbps) and 1394b

(which has a transfer speed of 800 Mbps).

Cables, connections and ports

Education