Basically, a communication system is composed by three parts: The transmitter is the first component. That’s the part of the communication system that sits at point A. It includes two items: the source of the information, and the technology that sends the information out over the channel. The second component is the channel. The channel is the medium (the conduct) that the information travels through in going from point A to point B. An example of a channel is optical fiber, or the air. Finally, there’s the receiver, the part of the communication system that sits at point B and gets all the information that the transmitter sends over the channel.
An example of communication system would be a conversation between you and one friend. The transmitter would be the person talking (and the two items would be the vocal cords and the windpipe). The channel in this example would be the air between persons speaking, and the Receiver would be the other person that is listening while the first one speaks.