How was the message transmitted ?
Shannon 's article laid out the basic elements of communication : An information source that produces a message A transmitter that operates on the message to create a signal which can be sent through a channel A channel , which is the medium over which the signal , carrying the information that composes the message , is sent A receiver , which transforms the signal back into the message intended for delivery A destination , which can be a person or a machine , for whom or which the message is intended It also developed the concepts of information entropy and redundancy , and introduced the term bit as a unit of information .