Data communication refers to the exchange of data between a source and a receiver. Data communication is said to be local if communicating devices are in the same building or a similarly restricted geographical area.The meanings of source and receiver are very simple. The device that transmits the data is known as the source and the device that receives the transmitted data is known as a receiver. Data communication aims at the transfer of data and maintenance of the data during the process, but not the actual generation of the information at the source and a receiver.