Data communication

Data Communication Components(Image Source: Data Communication and Networking By Behrouz A. Forouzan)

Data communication is the exchange of information between computers. Data communication is used to send and receive data. Email, Instant Messaging, Phone calls, electronic meetings and video conferencing are applications of data communication. Data communication involves both hardware and software. Data communication consists of five elements. Sender, Receiver, Message, transmission medium and protocol.

SENDER

The sender is the device or computer that sends data.

RECEIVER

The receiver is the device or computer which receives data from the sender.

MESSAGE

The message is data which user wants to send or receive. Data can be any format such as text, numbers image, and video.

TRANSMISSION MEDIUM

The transmission medium is the physical path which is used to send message between sender and receivers. The transmission medium plays an important role in data communication effectiveness. Fiber optic cable, coaxial cable, twisted pair cable, infrared and radio waves are types of the transmission medium.

PROTOCOL

A protocol is an agreement between two computers. It is sets of rules to be followed by both computers for data communication. If Computer A wants to communicate with Computer B then both have to follow some protocols. Let us understand the protocol by a general example, John wants to communicate with Shahzad. John is from the United States of America(USA) knows English and Shahzad from Pakistan know Urdu, so for communication, they developed a protocol that they will always talk in English so that they can communicate and understand each other. Same for computers, Computer A wants to communicate with Computer B, he will communicate with certain protocols.

Data communication performance depends on certain characteristics. An effective data communication system must have four characteristics, which are explained below.

1.               DELIVERY:

A sender that sends data to a specific computer must be delivered to that computer and no other computer would receive that data.

2.               ACCURACY

The computer must deliver data that should be accurate it should not be altered or changed during data transmission. The altered data is not usable and will affect the data communication system performance.

3.               TIMELINESS

The computer must deliver data at a certain time. The data which receives data late will be not useful. For example, in a video conferencing system if video is delivering after big delay then this application will be useless.

4.               JITTER

Data communication sends data in packets. If these packets will not be delivered by the communication system in order or there is a variation in arrival time then the message will be useless and the receiver will get the distorted or wrong message.

Tags: Data Communication, Computer Networks