Communication is t he process of establishing connection or link between two points for information exchange.Communication is simply the process of conveying message at a distance or communication is  the basic process of exchanging information.

The electronic equipments which are used for communication purposes, are called communication equipments. Different communications equipments, when assembled together form a communication system.

Typical examples of communication system are line telephony and line telegraphy, radio telephony and line telegraphy, radio broadcasting, point to point communication and mobile communication , computer communication, radar communication, television broadcasting, radio telemetry, radio aids to navigation , radio aids to aircraft landing etc.

The earliest communication system namely line telegraphy originated in eighteen century. In addition to this telephony came a few decades later whereas radio communication could become possible in the beginning of twentieth century on invention of triode valve. Radio communication was further greatly improved during World War 2. It become more widely used through the invention of transistor, integrated circuits and other semiconductor devices in the sub sequent years. Also in recent years communication has become more widespread with the use of satellites and fibre optics. Today there has been an increasing emphasis on the use of computers in communication.

Basic Communication System

The purpose of a communication system is to transmit an information bearing signal from a source located at one point, to a user or destination located at another point some distance  away shows the block diagram of a basic communication system in which the different functional elements are represented by blocks. The essential components of a basic communication system are information source, transmitter, communication channel, and receiver. This means that any communication system either simple or advance analog or digital must have these blocks.