Basic Communication Model

Communication is the transfer of a message from one entity, called the source or transmitter, to another, called the destination or receiver, via a channel of some sort.

The transfer of a message could be followed by a response message from the original destination to complete one cycle in a dialogue between corresponding entities. The only way that a message source can be certain that the destination properly received the message is by some kind of acknowledgement response form the destination. This acknowledgement form of dialogue is the basis of reliable communications-source must get feedback that the destination correctly received the massage.

Source: Device that generates the data to be passed on to the Destination device. It could be a user computer trying to make a query to a server computer.

Transmitter: if the data generated by the source device has to be transmitted through Transmission Channel or Transmission System the it has to be presented in a form that is acceptable to the Transmission system. This job is done by the Transmitter. For Example, a modem takes a digital bit stream from the attached computer and transforms that stream of bits into an analog signal which can be handled by the telephone network.

Transmission System: This can be a single transmission line connecting the two systems communicating or a complex network to which numerous communicating systems are connected.

Receiver: This receives the signal from the transmission system and converts it into a form that is suitable to the destination device. For example, a modem accepts analog signal from a transmission channel and transforms it into digital bits stream.

Destination: Device to which the source device sends data.