|Definition:|| part of a communication system that connects the message source with the message sink|
Note 1 to entry: An encoder can be inserted between the message source and the input to the channel, and a decoder between the output of the channel and the message sink. Generally, these two units are not considered as being parts of the channel. In certain cases, however, they can be considered as parts of the message source and message sink, respectively.
Note 2 to entry: In information theory according to Shannon, the channel can be characterized by the set of conditional probabilities of occurrence of all the messages received at the message sink when a given message emanates from the message source.