communications (used with a sing. or pl. verb)
The art and technique of using words effectively to impart information or ideas.
The field of study concerned with the transmission of information by various means, such as print or broadcasting.
Any of various professions involved with the transmission of information, such as advertising, broadcasting, or journalism.
Something communicated; a message.
communications A means of communicating, especially:
A system, such as mail, telephone, or television, for sending and receiving messages.
A network of routes for sending messages and transporting troops and supplies.
communications The technology employed in transmitting messages.

communication system - Communications is the field of study concerned with the transmission of information through various means. It can also be defined as technology employed in transmitting messages. It can also be defined as the inter-transmitting the content of data (speech, signals, pulses etc.) from one node to another.
A system or facility capable of providing information transfer between persons and equipment. The system usually consists of a collection of individual communication networks, transmission systems, relay stations, tributary stations, and terminal equipment capable of interconnection and interoperation so as to form an integrated whole. These individual components must serve a common purpose, be technically compatible, employ common procedures, respond to some form of control, and generally operate in unison.

Communication is divided in two types. They are

1. Analog Communication System

2.Digital Communication System