Data communication - what is data communication ?

Introduction of data communication

Data communication is the transmission of coded between  remote terminal and centralised computer installation or between two or more computer centre over established communication links .

Advantages of data communication

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Data communication image

Saving of time in data preparation and physical transportation of prepared data .

Full utilisations of proccessing power and storage capacity of modern computer .

Quick retrievel of information from files .

Elimination duplication of files .

Reduction the cost of data transmission .

Also read

Type of transmission channel

There are mainly two types of transmission channel

1 simplex channel =   sender A  - receiver B

In this channel transmission of data always in one direction i.e .after receiving the radio signal from radio station , the receiver can't send back the signal to radio station . Transmission always flow from A to B .

2 half duplex channel  = sender A - sender B

In this channel transmission of data in both directions , but any one instant of time it is only one in one direction . It means there is flow of transportation from either A to B or from at one time , such as telephone line .

3 Full duplex channel  = sender A- sender B

In this channel transmission of data is one both directions simultaneously . It means there is flow of transportation from A to B and from B to A at any instant of time .

Parity check

In communication party bit is used to check data that has been transmitted . The parity bit is added to every data unit that are transmitted . The parity bit is used to check data that has been transmitted accurately . The parity bit for each unit is set so that all  bytes have either an odd number or even number 1 s . Parity bit are used as the simplest form of error detecting code .

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Image for data communication 

Information transfer speeds

Information transfer speeds is measured by a bit and baud rate .
bit rate indicates the speed of bit transmitted within one second . Baud rate count the number of times of transmission change state .

Data communication channel

Data is transmitted from a terminal to a computer system or form a computer system to a terminal over communication channel which are also called communication lines or data links . They are following types .

1 standard telephone line

2 coxial cable

3 microwave transmission

4 settlite  communication

5. Fiber optics

1 Standard telephone line

It is widely used as communication channel .it's is very effective useful for the user of data communication because it is easy to join and the complex of network of telephone line  has been already established all over the world . It consists of two wires of copper covered with insulator .

2 Coxial cable 

These are high quality communication lines that has been under the ground or sea . These cables are also used for data communication . A type of wire that consist of a centre wire sorround by insulation and then a ground shield of braided wire . The shield minimise electrical and radio frequency interface . The layers of institutions help minimize  interface and distortion . Transmission speed range from 200 million to more than 500 million bits per second . Coxial cable television industry and is also widely used for computer networking , such as ethernet . Although is in more expensive than a standard telephone wire , it is much less susceptible  to interface and can carry much more data .

3  microwave transmission

It transmission signal through open space like radio signal .it provides a much faster transmission rate than telephone line or coxial cable .in this system data transmission on a line of  sight path and needs antenna . Microwave antenna are usually place on top of building ,towers , hills ,and mountains peak .it consists of serious of relay station approximate 30 miles apart .from transmission to long , distance , signal are amplifier are transmitted from station to station .it provides higher bandwidth but is affected by rain , dust , cloud and bad weather . It is used to cellular network and television broadcast .

4 satellite communications

satellite communications is known for fast communication . It is deal for a long distance communication . An artificial satellite intelligence position in space for the purpose of telecommunication. These satellite service and relay station for the transmission of signal generator from the earth .bthe satellite amplifier signal received from the earth station and retransmit the signal to another earth station which can be located many thousands of miles away . They are also used for mobile application such as a community to ship, vehicle , planes and hand held terminal and for TV and radio broadcasting .

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