ONGC_summer_rereport

Summer Training Report 2015 ONGC Hazira

A SUMMER INTERNSHIP REPORT ( 2015)

SUMMER TRAINING IN

ELECTRONICS AND COMMUNICATION

Submitted By:

Jayit Ghosh

PES Institute of Technology

USN- 1PI12EC041

Department of Electronics & Communication Engineering

PES Institute of Technology100 Feet Ring Road, BSK III Stage

Bangalore - 560 085June 2015

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CERTIFICATE

This is to certify that the following report is the bonafide work of JAYIT GHOSH (1PI12EC041), 3rd year ECE student of PES Institute of Technology, Bangalore, carried out under my supervision from May 2015 to July 2015.

Place: _________ _________________________________

Date: __________ (Supervisor)

Name:

Designation:

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INDEX

Sr. no.

Topic No.

1. Acknowledgements2. Radio Communication3. Satellite Communication4. CCTV Surveillance5. Telephone Exchange6. Computer Networking7. Server Control

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ACKNOWLEDGEMENTS

I am very thankful and obliged to the following people for giving a chance to learn from the esteemed company and its plethora of talented and knowledgeable people.

1. Mr. S Shrivasatava (DGM, E&T section)2. Mr. Naresh Singh(C.E, E&T section),mentor and guide throughout the

training period (Telephone Exchange)3. Mr. Irshad Khan(C.E, EDP Section), mentor and guide throughout the

training period(Networking and Server Control)4. Mr. Sanjeev Thapliyal, guide for Satellite Communication5. Mr. S.V Acharya, I/C of Training for providing this wonderful

opportunity.

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RADIO COMMUNICATION

Radio is the radiation (wireless transmission) of electromagnetic energy through space. The biggest use of radio waves is to carry information, such as sound, by systematically changing (modulating) some property of the radiated waves, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.

Radio systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation, angle modulation (which can be frequency modulation or phase modulation). Radio systems also need an antenna to convert electric currents into radio waves, and vice versa. An antenna can be used for both transmitting and receiving. The electrical resonance of tuned circuits in radios allow individual stations to be selected. The electromagnetic wave is intercepted by a tuned receiving antenna. A radio receiver receives its input from an antenna and converts it into a form usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc.[2] Radio frequencies occupy the range from a 3 kHz to 300 GHz, although commercially important uses of radio use only a small part of this spectrum.

A radio communication system sends signals by radio.[4] The radio equipment involved in communication systems includes a transmitter and a receiver, each having an antenna and appropriate terminal equipment such as a microphone at the transmitter and a loudspeaker at the receiver in the case of a voice-communication system.

Types of Radio Observed

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HF Communication

High Frequency (HF) radio provides aircraft with an effective means of communication over long distance oceanic and trans-polar routes. In addition, global data communication has recently been made possible using strategically located HF data link (HFDL) ground stations. These provide access to ARINC and SITA airline networks. HF communication is thus no longer restricted to voice and is undergoing a resurgence of interest due to the need to find a means of long distance data communication that will augment existing VHF and SATCOM data links.

An aircraft HF Radio system operates on spot frequencies within the HF spectrum. Unlike aircraft VHF radio, the spectrum is not divided into a large number of contiguous channels but aircraft allocations are interspersed with many other services, including short wave broadcasting, fixed point-to-point, marine and land-mobile, government and amateur services. This chapter describes the equipment used and the different modes in which it operates.

HF Range and Propagation

In the HF range (3MHz to 30 MHz) radio waves propagate over long distances due to reflection from the ionized layers in the upper atmosphere. Due to the variations in height and intensities of the ionized regions, different frequencies must be used at different times of the day and night and for different paths. There is also some seasonal variation (particularly between winter and summer). Propagation may also be disturbed and enhanced during periods of intense solar activity. The upshot of this is that HF propagation has considerable vagaries and is far less predictable than propagation at VHF. Frequencies chosen for a particular radio path are usually set roughly mid-way between the lowest usable frequency (LUF) and the maximum usable frequency (MUF). The daytime LUF is usually between 4 to 6 MHz during the day, falling rapidly after sunset to around 2 MHz The MUF is dependent on the season and sunspot cycle but is often between 8 MHz and 20 MHz Hence, a typical daytime frequency for aircraft communication might be 8 MHz whilst this might be as low as 3 MHz during the night. Typical ranges are in the region of 500km to 2500km and this effectively fills in the gap in

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VHF coverage.

Aircraft Communications And Navigation Systems

Propagation Characteristics

Since ionosphere often refracts HF radio waves quite well (sky wave propagation), this range is extensively used for media and long range radio communication. However, suitability of this portion of the spectrum for such communication varies greatly with the complex combination of factors: a) Sunlight/darkness at site of transmission and reception b) Transmitter/receiver proximity to terminator c) Season d) Sunspot cycle e) Solar activity f) Polar aurora

These and other factors, contribute at each point in time for a given communication path to aa) Maximum Usable Frequency (MUF) b) Lowest Usable Frequency (LUF) c) Frequency of optimum transmission (FOT)

SSB MODULATION:

Unfortunately, the spectrum available for aircraft communications at HF is extremely limited. As a result, steps are taken to restrict the bandwidth of transmitted signals, for both voice and data. Double Sideband (DSB) amplitude modulation requires a bandwidth of at least 7 KHz but this can be reduced by transmitting only one of the two sidebands. Either the upper sideband (USB) or the lower sideband (LSB) can be used because they both contain the same modulating signal information.In addition, it is possible to reduce (or ‘suppress’) the carrier as this, in itself, does not convey any information. In order to demodulate a signal

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transmitted w/o a carrier it is necessary to reinsert the carrier at the receiving end (this is done in the demodulator stage where a beat frequency oscillator or carrier insertion oscillator replaces the missing carrier signal at the final intermediate frequency).

The absence of the carrier means that less power is wasted in the transmitter which consequently operates at significantly higher efficiency.

HF Radio Equipment:

This equipment uses a single intermediate frequency (IF), but in practice most modern aircraft HF radios are much more complex and use two or three intermediate frequencies. On transmit mode, the DSB suppressed carrier is produced by means of a balanced modulator stage.

The balanced modulator rejects the carrier and its output just comprises the upper and lower sidebands. The DSB signal is then passed through a multiple stage crystal or mechanical filter. This filter has a very narrow pass band (typically 3.4 KHz) at intermediate frequency (IF) and this rejects the unwanted sideband. The resulting SSB signal is then mixed with a signal from the digital frequency synthesizer to produce a signal on the wanted channel.

The o/p from the mixer is then further amplified before being passed to the o/p stage. Note that, to avoid distortion all of the stages must operate in linear mode. When used on receive mode, the incoming signal frequency is mixed with the o/p from the digital frequency synthesizer in order to produce the IF signal. Unwanted adjacent channel signals are removed by means of another multiple stage crystal or mechanical filter which has a pass band similar to that used in a transmitter. The IF signal is then amplified before being passed to the demodulator.

The (missing) carrier is reinserted in the demodulator stage. The carrier signal is derived from an accurate crystal controlled carrier oscillator which

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operates at the IF frequency. The recovered audio signal from the demodulator is then passed to the audio amplifier where it is amplified to an app. Level for passing to a load speaker.

HF stations at ONGC, Hazira BPA P/F

BPB P/F

TAPTI P/F

PANNA FIELD

JUHU HELIBASE

VASUDHARA BHAVAN

TROMBAY

URAN

11 HIGH

VHF Communication

Very High Frequency is a term used to describe the 30MHz to 300MHz portion of the radio spectrum.

This range of frequencies will provide short-range LOS (line of site) communications.

The range for VHF communications will typically be 2 to 20miles depending on equipment used, antenna height, and terrain.

Characteristics:

Unlike HF frequencies, the ionosphere does not usually reflect VHF signals.

Signals are restricted to the local AO (area of operation).

VHF signals are less affected by atmospheric noise and interference from electrical equipment than HF signals.

Propagation:

VHF is very limited by terrain (foliage, buildings, and mountains).

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To use VHF, it is necessary to be able to visualize a direct line of site between the two stations.

There are two unusual conditions that can cause VHF signals to propagate farther than normal, tropospheric ducting and Sporadic-E.

While both of these conditions are possible neither is reliable and are hard to predict.

VHF signals travel fairly direct from one station to another.

When to use VHF:

VHF is the best choice to use when communications are needed to tie all personnel together in a localized area.

Examples:

i. In the immediate area where a mobile CP is set up. ii. Traffic control operations.

iii. Guard duty in an armory.

Range:

For handheld type radios, the communications range can be from several hundred feet to several miles.

With mobile and base VHF radios, which generally have higher output power, this range can be extended out to a much greater distance.

The type of antenna and the terrain are the two biggest factors that will influence VHF communications.

The use of a simple ground plane antenna can dramatically improve communications.

When possible, locate your CP or your antenna on the highest ground.

If not possible, mount the antenna up as high as is safely possible or practical.

Remember the line of site, the higher up the antenna, the more it can ‘see’.

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Dependency Factors:

VHF radio will work day in & day out with little concern for weather, time of day and time of year.

This is one reason that VHF has been preferred system to use by the military, police, rescue and fire department for years.

Forming a VHF station:

There are four basic things needed to assemble a VHF station:

a) VHF Transceiver b) Power Source c) Cabling d) Antenna

Power sources:

Most modern day VHF transceivers can operate from 12V DC supply.

This is very convenient when operating in an emergency operation where commercial power or fuel for a generator might be in short supply.

When commercial power or generator is available, a 12V DC supply is used.

To conserve battery power, use only the output power necessary to carry out the communications, i.e., if you are running high power and you can reliably carry out the communications with low power, switch to the low power position.

VHF Communication at ONGC: VHF Fixed: 20 Sets VHF Mobile: 6 Sets Walky Talky: 77 Sets VHF Stations at ONGC, Hazira:

Main Fire Station (CISF) Plant Main Gate (CISF) Additional Fire Station (CISF) LPG C/R Plant CO-GEN C/R Plant

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Radio Room Satellite Building Ubhrat Valve Station STF Control Room (CISF) Jeep DC Fire (CISF) Jeep Fire (CISF) Fire Tenders Product Terminal

SATELLITE COMMUNICATION

Communications satellites act as the middleman in the realm of telecommunications. These satellites are specifically designed to relay information from a source to a receiver. Types of information that can be transferred include: television, telephone, radio, internet, and military. As of May 11, 2015, there are over 2,000 communications satellites in Earth’s orbit that are being used by private and government organizations.[1]

In order to communicate wirelessly, signals must be sent using electromagnetic waves. However, these waves cannot bend around the curvature of the Earth. So, in order for people to communicate over long distances, a satellite (or multiple satellites) must be used to help redirect the signals.[2]

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https://en.wikipedia.org/wiki/Communications_satellite#cite_note-2



There are two major classes of communications satellites. The first class is called the “passive satellite”. This type of satellite only redirects the signal coming from the source, and points in the direction of the receiver. With passive satellites, the transmitting signal has the tendency to be weak. This is because, as the electromagnetic wave moves through the atmosphere, particles will interrupt the wave and cause it to be muffled. Active satellites, on the other hand, allow for a signal that is much clearer. These satellites can take a signal that they receive, and amplify it to make it clearer. However, these satellites will often times amplify unwanted signals. Because of this, they also need a processor on board. A processor will filter out any of the unwanted amplified signals before sending it back down to earth.[3]

There are three major ways in which communications satellites orbit the Earth. One of these orbits is called geosynchronous orbit (GEO), which is 19,300 nautical miles from Earth’s surface. This orbit has the special characteristic in which satellites placed in this orbit can “stand still” with respect to a certain location on earth. That is, if a viewer on Earth were to look up into the sky and spot a satellite in GEO, it would seem as if it isn’t moving. Below GEO is medium Earth orbit (MEO). It ranges from 500-1200 nautical miles above Earth. Below MEO is low Earth orbit (LEO) and is about 200 nautical miles above Earth. MEO and LEO are not able to keep satellites “stationary” like GEO, so more satellites would be needed to cover a certain area. However, they transmit clearer signals because of their relatively small distance to the earth. In this case, the contractor must make a decision to use more satellites in order to have a clearer signal, or use one satellite while having a muffled signal.[4]

The electromagnetic signals that communication satellites work with, have a large spectrum of wavelengths and frequencies. To keep these waves from interfering with one another, the United States and other international organizations have certain rules and regulations describing which wavelength a certain company or group can use. By separating out wavelengths, communication satellites will have minimal interference and be able to communicate effectively.

Types of Satellite:.

1. Geostationery Satellite:

To an observer on the earth, a satellite in a geostationary orbit appears motionless, in a

fixed position in the sky. This is because it revolves around the earth at the earth's

own angular velocity (360 degrees every 24 hours, in an equatorial orbit).

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https://en.wikipedia.org/wiki/Non-inclined_orbit


https://en.wikipedia.org/wiki/Low_Earth_orbit

https://en.wikipedia.org/wiki/Medium_Earth_orbit

https://en.wikipedia.org/wiki/Medium_Earth_orbit



A geostationary orbit is useful for communications because ground antennas can be

aimed at the satellite without their having to track the satellite's motion. This is relatively

inexpensive. In applications that require a large number of ground antennas, such

as Direct TV distribution, the savings in ground equipment can more than outweigh the

cost and complexity of placing a satellite into orbit.

2. Polar satellites:

A low Earth orbit (LEO) typically is a circular orbit about 200 kilometres (120 mi) above

the earth's surface[citation needed] and, correspondingly, a period (time to revolve around the

earth) of about 90 minutes. Because of their low altitude, these satellites are only visible

from within a radius of roughly 1,000 kilometers from the sub-satellite point. In addition,

satellites in low earth orbit change their position relative to the ground position quickly.

So even for local applications, a large number of satellites are needed if the mission

requires uninterrupted connectivity.

Low-Earth-orbiting satellites are less expensive to launch into orbit than geostationary

satellites and, due to proximity to the ground, do not require as high signal

strength (Recall that signal strength falls off as the square of the distance from the source,

so the effect is dramatic). Thus there is a trade off between the number of satellites and

their cost. In addition, there are important differences in the onboard and ground

equipment needed to support the two types of missions.

Satellite Frequency Bands

Frequency Bands Frequency Range(GHz)

L 1-2

S 2-4

C 4-8

S 8-12

Ku 12-18

K 18-27

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https://en.wikipedia.org/wiki/Wikipedia:Citation_needed

https://en.wikipedia.org/wiki/Low_Earth_orbit


Ka 27-40

O 40-50

V 50-70

The satellites that were observed were of type C band and Ku/ Band.

1. C band Satellite :

Frequency range:

NATO: 500-1000Mhz

IEEE C band: 4-8 GHz

C band is generally used for Wi-Fi connections, weather radar systems,

and a few cordless devices.

“Rain Fade” is collective name given for the adverse effects of weather

conditions.

C band performance is usually better than Ku band when it comes to

facing rain fade.

The diameter of the satellite observed was 7.5m

2. K u Band:

The term “Ku” stands for “K-under” band, i.e. the band directly below K-

band.

Operation: 12-18 GHz

It is majorly used as fixed or broadcast services, speed detection of

vehicles. A part of the band is used for ISS and NASA communications.

ADVANTAGES:

Unlike C band, it is not restricted by power, thus the power of its

uplinks and downlinks can be increased.

This reduces the size of the receiving dishes.

The parabolic reflectors are even more efficient in focusing the

receiving signals.

Satellite operator does not need to be highly accurate of the

satellite position.

DISADVANATGES:

Highly susceptible to “Rain Fade”

Also susceptible to “Snow Fade”, where snow/ ice precipitates are

collected in the dish during winters.

The diameter of the observed satellite was 2.4m.

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DAMA and PAMA

DAMA (Demand Assigned Multiple Access): PAMA (Permanently Assigned Multiple Access):

It is a technology used to assign a channel to clients that don’t need to use constantly. DAMA systems assign communication channels based on requests issued from user terminals to a network control systems. When the circuit is no longer in use, the channels are then returned to the central pool for re-assignment to other users. Channels are typically a pair of carrier frequencies, one for transmit and one for receive.

It allows utilizing of one channel by many users sequentially at different times. This technology is mainly useful with sparsely used networks of transient clients, as opposed to PAMA (Permanently Assigned Multiple Access). By using DAMA technology, the number of separate nodes that can use a limited pool of circuits can be greatly increased at the expense of no longer being able to provide simultaneous access for all possible pairs of nodes.

A five channel DAMA network can only have 5 simultaneous conversations but could have any number of nodes. A 5 channel PAMA network permanently supports 5 simultaneous conversations with channel ownership remaining with their permanently assigned nodes even when idle.

DAMA and PAMA are related to channel/resource allocation and should not be confused with multiple accesses/multiplexing methods (such as FDMA frequencies, TDMA slots, CDMA code or others) intended to divide a single communication channel into multiple virtual channels. This system typically

use resource allocations protocols that allow more rapid near real time allocation of bandwidth based on demand and data priority.

However, in sparsely allocated multiple access channels, DAMA can be used to allocate the individual virtual channel resources provided by the multiple access channel. DAMA is widely used in satellite communications, especially in VSAT systems. It is very effective in environments comprising multiple users each having a low to moderate usage profile. DAMA is often used in military environments due to the relative simplicity of implementation, ease of modelling and the fact that military usage profiles are good fit.

PAMA is a permanently assigned frequency channel that provides dedicated band width,

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through which one sends data, voice or video.

Details of Satellite used by ONGC Hazira:Satellite: GSAT 10Location: 83 degrees EASTTransponder No.: 15Transponder Bandwidth: 36MHzTransponder Centre Frequency: 6050/3825 MHzPolarization: LINEAR

Geostationary orbit

To an observer on the earth, a satellite in a geostationary orbit appears motionless, in a fixed position in the sky. This is because it revolves around the earth at the earth's own angular velocity (360 degrees every 24 hours, in an equatorial orbit). A geostationary orbit is useful for communications because ground antennas can be aimed at the satellite without their having to track the satellite's motion. This is relatively inexpensive. In applications that require a large number of ground antennas, such as Direct TV distribution, the savings in ground equipment can more than outweigh the cost and complexity of placing a satellite into orbit.

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https://en.wikipedia.org/wiki/DirectTV


GSAT-10

GSAT-10 is an Indian communication satellite which was launched by Ariane-5ECA carrier rocket in September 2012. It has 12 KU Band, 12 C Band and 6 lower extended c band transponders, and included a navigation payload to augment GAGAN capacity. Following its launch and on-orbit testing, it was placed in geosynchronous orbit at 83.0° East, from where it will provide communication services in India.

GSAT-10, with a design life of 15 years was operational by November 2012 and will augment telecommunication, Direct-To-Home and radio navigation services. At 3,400 kg at lift-off, it is the heaviest built by Bangalore-headquartered Indian Space Research Organization.

It was ISRO's 101st space mission. Arianespace's heavy lifting Ariane-5 ECA rocket launched the satellite about 30 minutes after the blast off from the European launch pad in South America at 2.48 am, prior to which it injected European co-passenger ASTRA 2F into orbit. GSAT-10 carries 30 transponders

(12 Ku-band, 12 C-band and six Extended C-Band), which will provide vital augmentation to INSAT/GSAT transponder capacity.

The GAGAN payload will provide improved accuracy of GPS signals (of better than seven meters which will be used by Airports Authority of India for civil aviation requirements. This is the second satellite in INSAT/GSAT constellation with GAGAN payload after GSAT-8, which was launched in May 2011.

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CCTV Surveillance System

Closed-circuit television (CCTV), also known as video surveillance, is the use of video

cameras to transmit a signal to a specific place, on a limited set of monitors. It differs

from broadcast television in that the signal is not openly transmitted, though it may employ point

to point (P2P), point to multipoint, or mesh wireless links. Though almost all video cameras fit

this definition, the term is most often applied to those used for surveillance in areas that may

need monitoring such as banks, casinos, airports, military installations, and convenience

stores. Video telephony is seldom called "CCTV" but the use of video in distance education,

where it is an important tool, is often so called.

In industrial plants, CCTV equipment may be used to observe parts of a process from a central

control room, for example when the environment is not suitable for humans. CCTV systems may

operate continuously or only as required to monitor a particular event. A more advanced form of

CCTV, utilizing digital video recorders (DVRs), provides recording for possibly many years,

with a variety of quality and performance options and extra features (such as motion

detection and email alerts). More recently, decentralized IP cameras, some equipped with

megapixel sensors, support recording directly to network-attached storage devices, or internal

flash for completely stand-alone operation. Surveillance of the public using CCTV is particularly

common in many areas around the world. In recent years, the use of body worn video cameras

has been introduced as a new form of surveillance.

Types of Cameras used:

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There are generally 12 types of cameras used for any security system.

1. Bullet: A bullet CCTV camera is a wall-mount or ceiling-mounted unit that is typically designed for indoor use, but can also be fill some outdoor applications. The camera derives its name from its sleek, thin cylindrical shape. Many bullet cameras also tout themselves as being waterproof. The camera is not typically designed to have pan/tilt/zoom control but instead to capture images from a fixed area. The unit is mounted pointing at a particular area.

2. Dome: A dome cameras get their name from the dome-shaped housing in which they sit. These housings are designed to make the cameras unobtrusive… not covert or hidden. Typical applications are retail, where the camera is designed to be unobtrusive, but visible.These units serve a dual purpose: “bad guys” will know the facility is being watched and patrons will feel at ease knowing the facility is being protected. Units that allow the camera to spin quickly within the housing are often referred to as “speed domes.”

3. Covert/Desktop/Board Cameras: These tiny cameras are well suited for desktop use for Skype and other low-resolution teleconference applications.

4. Discreet Cameras: It’s clock… it’s a smoke detector… it’s motion sensor. The real answer is none of the above. These are just some of the disguises for covert cameras. Of course, covert cameras can also be characterized by conventional cameras placed in discreet locations.

5. Infrared/Night Vision: These night-vision cameras have the ability to see images in pitch black conditions using IR LEDs. In some cases they are for mobile applications.

6. Outdoor: The key to outdoor cameras is the housing itself, which must be impenetrable to moisture, insects, dust and other elements.

7. Day/Night: Day/night cameras compensate for varying light conditions to allow the camera to capture images. These are primarily used in outdoor applications where the security camera is positioned for an outdoor parking lot, for example. In many cases, units are dubbed as having a wide dynamic range to function in glare, direct sunlight, reflections and strong backlight 24/7.

8. Varifocal: A camera with a varifocal lens allows the operator to zoom in or out while still maintaining focus on the image.

9. Network/IP: These cameras, both hardwired and wireless, transmit images over the Internet, often compressing the bandwidth so as not to overwhelm the web. IP cameras are easier to install than analog cameras because they do not require a separate cable run or power boost to send images over a longer distance.

10. Wireless: Not all wireless cameras are IP-based. Some wireless cameras can use alternative modes of wireless transmission. But no matter what the transmission method, the primary benefit to these units is still the same: extreme flexibility in installation.

11. PTZ/Speed Domes: Pan/tilt/zoom cameras give the surveillance operator the ability to move the camera left or right (pan); up and down (tilt); and zoom the lens closer or

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farther. These are relegated to surveillance situations where there is an actual live guard or surveillance specialist monitoring the images. There are cameras that have automated pan/tilt/zoom functionality where the camera is moving on a timed basis. These are many times used to cover a wide area with only one camera, or to avoid poor light conditions, such as a setting sun.

12. High-Definition Cameras: Ultra high-definition cameras are often relegated to

niche markets, such as casinos. These give the operators the ability to zoom in with extreme clarity (to look at poker players, for example, who might have something up their sleeve). In the past, these cameras were tube-based analog cameras, but today’s digital technology has displaced those older units. The cameras can also transmit their images using HDcctv.

.

Retention, storage and preservation

Most CCTV systems may record and store digital video and images to a digital video

recorder (DVR) or, in the case of IP cameras, directly to a server, either on-site or offsite.

There is a cost in the retention of the images produced by CCTV systems. The amount and

quality of data stored on storage media is subject to compression ratios, images stored per

second, image size and is effected by the retention period of the videos or images.[66] DVRs store

images in a variety of proprietary file formats. Recordings may be retained for a preset amount

of time and then automatically archived, overwritten or deleted, the period being determined by

the organisation that generated them.

21

https://en.wikipedia.org/wiki/Proprietary_file_format

https://en.wikipedia.org/wiki/Closed-circuit_television#cite_note-JVSG_Video_Compression_Guide_2010-67


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Telephone Exchange System

Basic Telephone Exchange System

Operator manages the entire system.Switching happens automaticallySystem also accomodates broadband data

Operator does the switching manuallySystem supports only voice

IC-NET(Integrated Communication Network)

SATELLITE BASED COMMUNICATION NETWORK NETWORK CONTROL CENTRE AT URAN EARTH STATION DATA CHANNELS ARE OPERATING IN PERMANENT ASSIGNED MULTIPLE

ACCESS (PAMA) MODE

Data Communication via IC-NET

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Total 5 types Modems providing data connectivity for application: SWAN (SAP WEB ADD ON) – Telephone and Welfare

SHRAMIK (System of Human Resources Automated Management Information for Kaizen)

ICE (Information Consolidation for Efficiency) VLS (Virtual Learning System) EPINET (Exploration and Production Information Network) IMPETUS (Implementing Maintenance and Procurement Efforts through

Upgraded System) VOICE COMMUNICATION VIA IC-NET

Total 10 VOICE CHANNELS providing voice connectivity to:

MR : URAN, PANVEL, VASUDHARA, OFFSHORE PLATFORM, HAZIRA

ER : NAZIRA, SILCHAR, JORHAT, SIBSAGAR

WR : VADODARA, ANKLESHWAR, AHMEDABAD, MEHSANA, CAMBAY, JODHPUR

CR : AGARTALA, KOLKATTA SR : RAJAMUNDARY, NARSAPUR, KARAIKAL HQ : DEHRADUN CHQ : NEW DELHI

INMARSAT TELEPHONE

Inmarsat is an international telecommunication company founded in 1979, originally as an intergovernmental organization. It operates a fleet of eleven geosynchronous telecommunication satellite.Inmarsat provides telephony and data services to users world-wide via special

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digital radios called “terminals”. An Inmarsat terminal contacts the satellite and communicates to a ground station through the satellite. It provides reliable communication services to a range of government, aid on agencies, media outlets and business needing to communicate in remote regions or where there is no reliable terrestrial network.

Services include traditional voice calls, low-level data tracking system and high speed data services as well as distress and safety services. The most recent of these provide GPRS-type services at upto 144kbps via the BGAN IP satellite. Modem is of the size of a notebook computer. Other services provide mobile ISDN services used by the media for live reporting on the world events via videophone.

Newer services using IP technology features an always-on capabilities where the users are simply charged for the amount of data they send and receive rather than length of time they are online. The satellite is digital transponders that receive digital signals, reform the pulses and then retransmit them to the ground. The ground station performs billing and act as gateways to the public switched telephone network and internet.

TELEPHONE EXCHANGE

In the field of telecommunications, a telephone exchange or telephone switch is a

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system of electronic components that connects telephone calls. A central office is the physical building used to house inside plant equipment including telephone switches, which make telephone calls ‘work’ in the sense of making connections and relaying the speech information. The term exchange area can be used to refer to an area served by a particular switch, but is typically known as a wire centre in the US telecommunications industry.

Manual service exchanges

With manual service, the customer lifts the receiver off-hook and asks the operator to connect the call to a requested number. Provided that the number is in the same central office, and located on the operator's switchboard, the operator connects the call by plugging the ringing cord into the jack on the switchboard corresponding to the called customer's line. If the called party's line is on a different switchboard in the same office, or in a different central office, the operator plugs into the trunk for the destination switchboard or office and asks the operator answering (known as the "B" operator) to connect the call.

Early automatic exchanges

Automatic exchanges, or dial service, came into existence in the early 1900s. Their purpose was to eliminate the need for human

switchboard who completed the connections required for a telephone call. Automation replaced human operators with electromechanical systems and telephones were equipped with a dial by which a caller transmitted the destination telephone number to the automatic switching system.

A typical satellite PBX with front cover removed.

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Digital switches

Digital switches work by connecting two or more digital circuits, according to a dialed telephone number or other instruction. Calls are set up between switches. In modern networks, this is usually controlled using the Signaling System 7 (SS7) protocol, or one of its variants. Many networks around the world are now transitioning to voice over IP technologies which use Internet-based protocols such as the Session Initiation Protocol (SIP). These may have superseded TDM and SS7 based technologies in some networks.

Each switch typically serves 10,000-100,000+ subscribers depending on the geographic area

PBX

A private branch exchange (PBX) is a telephone exchange that serves a particular business or office, as opposed to one that a common carrier or telephone company operates for many businesses or for the general public. They are also referred to as: PABX – Private Automatic Branch Exchange EPABX – Electronic Private Automatic Branch Exchange

PBX FUNCTIONS - They have functionally four main call processing duties:

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1. Establishing connections (circuits) between the telephone sets of two users.

2. Maintaining such connections as long as the users require them. 3. Disconnecting those connections as per the user’s requirement. 4. Providing information for accounting purposes.

EPABX SYSTEM AT ONGC, HAZIRA

The EPABX system at Hazira provides internal communication among different areas and offices within the plant as well as between two colonies and plant.

Level DID (Direct Inward Dialing) facility from BSNL to about 975 extensions by Prefixing 287 to four digits EPABX no. (287xxxx).

Access to all outside lines through “0” dialing. Corporation wide satellite communication through IC-NET. Four EPABX are in operation as below:

1. DEFINITY (Lucent Technologies) model G3Si Location: SES, Hazira Plant

Capacity: 550 lines. Expandable up to 2400 lines Subscribers: 525 lines Installed in: Year 2004

Interfaced with ONGC Captive Communication Network (ICNET, BPA)

2. DEFINITY (AVAYA) Master Exchange Model G3-R Location: SES, Hazira Plant

Subscribers: 525 lines Installed in: Year 2004 Supplier: AVAYA GLOBAL CONNECT PVT. LTD.

3. DEFINITY (AVAYA) Remote Exchange Location: Phase-I ONGC Colony

Capacity: 700 lines. Expandable up to 800 lines Subscribers: 650 lines Installed in: Year 2004 Supplier: AVAYA GLOBAL CONNECT PVT. LTD.

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4. DEFINITY (AVAYA) Remote Exchange Location: Phase-II ONGC Colony

Capacity: 350 lines. Expandable up to 800 lines Subscribers: 200 lines Installed in: Year 2004 Supplier: AVAYA GLOBAL CONNECT PVT. LTD.

Both exchanges are: Interfaced with PSTN (BSNL) for communication outside ONGC

through “0” dialling. Interfaced with Master Exchange at SES, Hazira Plant through fibre

optic cable.

ONGC Hazira has a total of 125 BSNL Land Lines and also has mobile services provided by BSNL under special mutual agreement with ONGC.

Paging System

PAGING INTRODUCTION

Paging is a one-way communications system. Paging allows callers to forward information to anyone with a pager and within the system coverage boundaries. System users can directly page people via the telephone system or through a dispatch message centre. Paging information will be either, a tone only page, a voice page or a display page. A tone only page refers to the user being alerted with no information following.

The alert inherently implies that the user should call some predetermined number to retrieve messages or information that awaits. This type of paging is very specific and mainly used by dispatch services. A voice page allows the user to send a finite length speech message directly from any telephone to the pager. This type of paging is quite useful since it is easy to use and requires no special equipment besides a telephone.

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The paging system alerts the subscriber and delivers a direct and to the point message where a return call is not necessary. This type of service however has potential draw backs since it uses up much system air time, receiver audio quality can be poor in some coverage areas making the message difficult to hear or it can be difficult to hear if received in a high noise environment.

Display paging refers to the user receiving either numeric or alpha numeric information on an LCD display. Numeric display is the most popular because it is easy to access from any touch tone phone system and air time usage is lower. The user can only enter return phone numbers or some special numeric codes defined specifically by individual users.

Alphanumeric display paging allows the user to send text messages. This requires special data entry equipment (typically operator-dispatched). Thesystem operator and pager model determine alphanumeric message lengths. Alphanumeric is growing in popularity however it requires maximum air time and data entry services.

Radio Paging at ONGC

1. SYSTEM IS MOTOROLA “PEOPLE FINDER LT/PLUS”. 2. CAPACITY 999 INDIVIDUALS OR MAX. 75 IN A GROUP. 3. GP NO. 700(GEN) AND GP NO. 100(DMP).

Plant paging systemDCSFCSMCSWALKIE-TALKIE

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Networking

Description:

There are so many different types of computer networks in existence, it can be hard to understand the differences between them, particularly the ones with very similar-sounding names. This lesson explains the structures and functions of some of the most popular computer networks.

Types of Networks:

There are several different types of computer networks. Computer networks can be characterized by their size as well as their purpose.

The size of a network can be expressed by the geographic area they occupy and the number of computers that are part of the network. Networks can cover anything from a handful of devices within a single room to millions of devices spread across the entire globe.

Some of the different networks based on size are:

Personal area network, or PAN Local area network, or LAN Metropolitan area network, or MAN Wide area network, or WAN

In terms of purpose, many networks can be considered general purpose, which means they are used for everything from sending files to a printer to accessing the Internet. Some types of networks, however, serve a very particular purpose. Some of the different networks based on their main purpose are:

Storage area network, or SAN Enterprise private network, or EPN

Virtual private network, or VPN

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Personal Area Network:

A personal area network, or PAN, is a computer network organized around an individual person within a single building. This could be inside a small office or residence. A typical PAN would include one or more computers, telephones, peripheral devices, video game consoles and other personal entertainment devices.

If multiple individuals use the same network within a residence, the network is sometimes referred to as a home area network, or HAN. In a very typical setup, a residence will have a single wired Internet connection connected to a modem. This modem then provides both wired and wireless connections for multiple devices.

The network is typically managed from a single computer but can be accessed from any device.

This type of network provides great flexibility,it allows you to:

Send a document to the printer in the office upstairs while you are sitting on the couch with your laptop.

Upload the photo from your cell phone to your desktop computer.

Watch movies from an online streaming service to your TV.

Local Area Network:

A local area network, or LAN, consists of a computer network at a single site, typically an individual office building. A LAN is very useful for sharing resources, such as data storage and printers. LANs can be built with relatively inexpensive hardware, such as hubs, network adapters and Ethernet cables.

The smallest LAN may only use two computers, while larger LANs can accommodate thousands of computers. A LAN typically relies mostly on wired connections for increased speed and security, but wireless connections can also be part of a LAN. High speed and relatively low cost are the defining characteristics of LANs.

LANs are typically used for single sites where people need to share resources among themselves but not with the rest of the outside world.

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Metropolitan Area Network:

A metropolitan area network, or MAN, consists of a computer network across an entire city, college campus or small region. A MAN is larger than a LAN, which is typically limited to a single building or site. Depending on the configuration, this type of network can cover an area from several miles to tens of miles. A MAN is often used to connect several LANs together to form a bigger network. When this type of network is specifically designed for a college campus, it is sometimes referred to as a campus area network, or CAN.

Wide Area Network:

A wide area network, or WAN, occupies a very large area, such as an entire country or the entire world. A WAN can contain multiple smaller networks, such as LANs or MANs. The Internet is the best-known example of a public WAN.

Private Networks:

One of the benefits of networks like PAN and LAN is that they can be kept entirely private by restricting some communications to the connections within the network. This means that those communications never go over the Internet.

Networking Cable:

Cable is the medium through which information usually moves from one network device to another. There are several types of cable which are commonly used with LANs. In some cases, a network will utilize only one type of cable, other networks will use a variety of cable types. The type of cable chosen for a network is related to the network's topology, protocol, and size. Understanding the characteristics of different types of cable and how they relate to other aspects of a network is necessary for the development of a successful network.

Unshielded Twisted Pair Connector:

The standard connector for unshielded twisted pair cabling is an RJ-45 connector. This is a plastic connector that looks like a large telephone-style connector. A slot allows the RJ-45 to be inserted only one way. RJ stands for Registered Jack, implying that the connector follows a standard borrowed from the telephone industry. This standard designates which wire goes with each pin inside the connector.

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Shielded Twisted Pair (STP) Cable:

Although UTP cable is the least expensive cable, it may be susceptible to radio and electrical frequency interference (it should not be too close to electric motors, fluorescent lights, etc.). If you must place cable in environments with lots of potential interference, or if you must place cable in extremely sensitive environments that may be susceptible to the electrical current in the UTP, shielded twisted pair may be the solution. Shielded cables can also help to extend the maximum distance of the cables.

Coaxial Cable:

Coaxial cabling has a single copper conductor at its center. A plastic layer provides insulation between the center conductor and a braided metal shield.The metal shield helps to block any outside interference from fluorescent lights, motors, and other computers.Although coaxial cabling is difficult to install, it is highly resistant to signal interference.

Thick coaxial cable is also referred to as thicknet. 10Base5 refers to the specifications for thick coaxial cable carrying Ethernet signals. The 5 refers to the maximum segment length being 500 meters. Thick coaxial cable has an extra protective plastic cover that helps keep moisture away from the center conductor. This makes thick coaxial a great choice when running longer lengths in a linear bus network. One disadvantage of thick coaxial is that it does not bend easily and is difficult to install.

Fiber Optic Cable:

Fiber optic cabling consists of a center glass core surrounded by several layers of protective materials.It transmits light rather than electronic signals eliminating the problem of electrical interference. This makes it ideal for certain environments that contain a large amount of electrical interference. It has also made it the standard for connecting networks between buildings, due to its immunity to the effects of moisture and lighting.

Fiber optic cable has the ability to transmit signals over much longer distances than coaxial and twisted pair. It also has the capability to carry information at vastly greater speeds. This capacity broadens communication possibilities to include services such as video conferencing and interactive services. The cost of fiber optic cabling is comparable to copper cabling; however, it is more difficult to install.

Cable Configurations:

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There are two common types of fiber cables -- single mode and multimode. Multimode cable has a larger diameter; however, both cables provide high bandwidth at high speeds. Single mode can provide more distance, but it is more expensive.

SERVER CONTROL

Contents:

Server-side technologies are quite numerous and diverse. Popular server side web application

technologies include:

Microsoft ASP/.NET

Java server technologies such as J2EE, JSP, and servlets

CGI / Perl

PHP

ColdFusion

In addition, the server-side technologies include database systems such as Oracle, SQL Server

(Microsoft), MySQL (open source) and many others.

Network Arrangement Topology:

The physical topology of a network refers to the configuration of cables, computers, and other peripherals. Physical topology should not be confused with logical topology which is the method used to pass information between workstations.

Main Types of Physical Topologies:

The following sections discuss the physical topologies used in networks and other related topics.

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Linear Bus Star Tree (Expanded Star) Considerations When Choosing a Topology Summary Chart

Linear Bus:

A linear bus topology consists of a main run of cable with a terminator at each end. All nodes (file server, workstations, and peripherals) are connected to the linear cable.

Advantages of a Linear Bus Topology:

Easy to connect a computer or peripheral to a linear bus. Requires less cable length than a star topology.

Disadvantages of a Linear Bus Topology:

Entire network shuts down if there is a break in the main cable. Terminators are required at both ends of the backbone cable. Difficult to identify the problem if the entire network shuts down. Not meant to be used as a stand-alone solution in a large building.

Star Topology:

A star topology is designed with each node (file server, workstations, and peripherals) connected directly to a central network hub, switch, or concentrator.

Data on a star network passes through the hub, switch, or concentrator before continuing to its destination. The hub, switch, or concentrator manages and controls all functions of the network. It also acts as a repeater for the data flow. This configuration is common with twisted pair cable; however, it can also be used with coaxial cable or fiber optic cable.

Advantages of a Star Topology

Easy to install and wire.

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No disruptions to the network when connecting or removing devices. Easy to detect faults and to remove parts.

Disadvantages of a Star Topology

Requires more cable length than a linear topology. If the hub, switch, or concentrator fails, nodes attached are disabled. More expensive than linear bus topologies because of the cost of the hubs, etc.

Tree or Expanded Star

A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable .Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs.

Advantages of a Tree Topology

Point-to-point wiring for individual segments. Supported by several hardware and software venders.

Disadvantages of a Tree Topology

Overall length of each segment is limited by the type of cabling used.

If the backbone line breaks, the entire segment goes down. More difficult to configure and wire than other topologies.

Network Hardware Devices:

File/Network Servers:

One or more network servers is a part of nearly every local area network.These are very fast computers with a large amount of RAM and storage space, along with a one or more fast network interface card(s). The network operating system provides tools to share server resources and information with network users. A sophisticated permissions-handling system is included, so that access to sensitive information can be carefully tailored to the needs of the users. For small networks, a singe network server may provide access control, file sharing, printer sharing, email, database, and other services.

The network server may be responding to requests from many network users simultaneously. The following guidelines should be followed:

Fastest processor(s) Large amount of RAM

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http://fcit.usf.edu/network/glossary.htm#RAM


multiple large, fast hard drives Extra expansion slots Fast network interface card(s) A RAID (Redundant Array of Inexpensive Disks) to preserve large amounts of data(even after a

disk failure) A back-up unit (i.e. DAT tape drive, removable hard drives, or CD/DVD/BluRay burner)

Workstations:

Computers that humans use are broadly categorized as workstations. A typical workstation is a computer that is configured with a network interface card, networking software, and the appropriate cables. Workstations do not necessarily need large storage hard drives, because files can be saved on the file server. Almost any computer can serve as a network workstation.

Laptops/Mobile Devices:

Laptops and other mobile devices are becoming more and more common. These devices typically have modest internal storage, but enough power to serve as a workstation for users on the go. These machines nearly always have a wireless adapter to allow quick network connections without cumbersome cabling. In a school environment with good wireless coverage, a mobile device user can move about the campus freely, and remain continuously connected to the network.

Network Interface Cards:

The network interface card (NIC) provides the physical connection between the network and the computer workstation. Most NICs are internal, and they are included in the purchase of most computers. Network interface cards are a major factor in determining the speed and performance of a network. It is a good idea to use the fastest network card available for the type of workstation you are using.

The most common network interface connections are Ethernet cards and wireless adapters.

Ethernet Cards

Ethernet cards are usually included with a computer, although additional ethernet cards can be purchased and installed on most computers,. Ethernet cards can contain connections for either coaxial or twisted pair cables (or both). If it is designed for coaxial cable, the connection will be BNC. If it is designed for twisted pair, it will have a RJ-45 connection. Some Ethernet cards also contain an AUI connector. This can be used to attach coaxial, twisted pair, or fiber optics cable to an Ethernet card. When this method is used there is

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always an external transceiver attached to the workstation. Only the RJ-45 connector is found on most modern Ethernet cards.

Wireless Adapters:

Wireless adapters are found in most portable devices, such as laptops, smart phones, and tablet devices. External wireless adapters can be purchased and installed on most computers having an open USB (Universal Serial Bus) port, or unused expansion slot. (See the Cabling section for more information on connectors.)

Switches:

An ethernet switch is a device that provides a central connection point for cables from workstations, servers, and peripherals. In a star topology, twisted-pair wire is run from each workstation to a central switch/hub. Most switches are active, that is they electrically amplify the signal as it moves from one device to another. The predecessor of the switch was the hub, which broadcasted all inbound packets out all ports of the device, creating huge amounts of unnecessary network traffic.

Repeaters:

Since a signal loses strength as it passes along a cable, it is often necessary to boost the signal with a device called a repeater. The repeater electrically amplifies the signal it receives and rebroadcasts it. Repeaters can be separate devices or they can be incorporated into a concentrator. They are used when the total length of your network cable exceeds the standards set for the type of cable being used.

A good example of the use of repeaters would be in a local area network using a star topology with unshielded twisted-pair cabling. The length limit for unshielded twisted-pair cable is 100 meters. The most common configuration is for each workstation to be connected by twisted-pair cable to a multi-port active concentrator. The concentrator amplifies all the signals that pass through it allowing for the total length of cable on the network to exceed the 100 meter limit.

Bridges:

A bridge is a device that allows you to segment a large network into two smaller, more efficient networks. If you are adding to an older wiring scheme and want the new network to be up-to-date, a bridge can connect the two.

A bridge monitors the information traffic on both sides of the network so that it can pass packets of information to the correct location. Most bridges can "listen" to the network and automatically figure out the address of each computer on both sides of the bridge. The bridge can inspect each message and, if necessary, broadcast it on the other side of the network.

The bridge manages the traffic to maintain optimum performance on both sides of the network. You might say that the bridge is like a traffic cop at a busy intersection during rush hour. It keeps information flowing on both sides of the network, but it does not allow unnecessary traffic through. Bridges can be used to connect different types of cabling, or physical topologies. They must, however, be used between

networks with the sameprotocol.

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Routers:

Routers are the traffic directors of the global internet. All routers maintain complex routing tables which allow them to determine appropriate paths for packets destined for any address. Routers communicate with each other, and forward network packets out of or into a network. Here's an example:

Routers are network gateways. They move network packets from one network to another, and many can convert from one network protocol to another as necessary. Routers select the best path to route a message, based on the destination address of the packet. The router can direct traffic to prevent head-on collisions, and is smart enough to know when to direct traffic along back roads and shortcuts.

Firewall:

A firewall is a networking device that is installed at the entrance to a LAN when connecting a networks together, particularly when connecting a private network to a public network, such as the internet.

Firewalls are either hardware or software, depending on their intended use. A firewall used to protect a network is a hardware device that should be installed in the network between the router and the network. Almost all hardware firewalls will have at least two ports, labeled "Trusted" and "Untrusted".

Firewall rules are usually simple, consisting of a verb, either allow or deny, the direction of the traffic, either inbound or outbound, and an address or other network traffic identifier. Firewall rules are cumulative, so general rules may be specified, and exceptions added as necessary. Some examples are:

Allow outbound all (all private network users can do anything on the public network) Deny inbound all (default setting to prevent all traffic from the public or untrusted port, to the

private port) Allow inbound port 80 (allow internet web traffic to come into network to find web servers) Allow inbound port 80 destined to 170.200.201.25 (allow inbound web traffic to a specific web

server on your private network) Deny inbound from 201.202.1.1/24 (deny all inbound traffic from a specific IP address or range

of addresses)

------------------------------------------------THE END------------------------------------------------------

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ONGC_summer_rereport

Documents

radio communication

radio systems

radio receiver

summer training report

radio communication

radio equipment

communication systems

biggest use of radio