The exchange of data between two devices via some form of transmission medium such as wire cable etc.
Tele is a Greek word for “Far”, so the Communication at a distance is known as Tele communication.
It includes telephony, telegraphy and television.
Types of communication:
Communication between two devices can be simplex, half duplex and full duplex.
The communication is unidirectional (One way communication).
In this type only one of the two devices on a link can transmit, the other can only receive.
Keyboard is an example, as it can only input the data.
Radio, TV are also example of Simplex Mode.
Two way communication but one at a time.
In this type of communication when one device is sending the other can only receive and vice versa.
Walkie- talkies are example of Half Duplex.
Two way communication simultaneously.
In this type of communication devices can send and receive the data at the same time.
Telephone is one common example of full duplex.