A protocol is a set of mutually accepted and implemented rules at both ends of the Communication channel for the proper exchange of information. Protocols comprise standards which at a basic level include the dimensions of line set-up, transmission mode, code set, and non-data exchanges of information such as error control (detection and correction).
To establish a meaningful session. a certain set of rules need to be adopted by \condors of networking Figure shows the basic configuration of data communication system. The numbers show in the figure indicate the following components of network:
(1) Data Transmission Line
- (2) Data Circuit Terminating Equipment (DCE) Modem or DSU (Digital Signal Unit)
- (3) Interface Data Terminal Equipment (L)TE) and DCE
- (4) Communication program on DTE
- (5) Communications Program on Communication Control Processor (CCP)
If the interface provided between (2) and (3) is not physically compatible, the DIE and DCE cannot be connected. And, even if they can be physically connected the DTE and the host cannot communicate with each other if the communication procedures