Data Communication refers to the exchange of data between the sender and the receiver.There are basically five elements of data communication:- 1. Message: It is the information or the data to be communicated.It may be in the form of text, numbers, pictures, sound, video or any other physical quantities. 2. Sender: It is the device which sends the data.It can be computers, workstations, telephone etc. 3. Receiver: It is the device which receives the message.It can be computers, workstations, television etc. 4. Transmission Medium: It is the physical path by which the message travels from sender to the receiver.It could be a twisted pair cable, fibre optic cable, microwaves, infrared waves etc. 5. Protocol : A protocol is a set of rules that govern data communications. It establishes an agreement between the communicating devices. Without a protocol, two devices may be connected but cannot communicate with each other. The protocols are being embedded wi...