We often send and receive data or information from one place to another when needed. Data communication is the process of sending and receiving. That is , the process of transferring data from one computer to another or from one device to another (mobile , smartphone , personal digital assistant , GPS navigator, etc.) or from one place to another or from one place to another is called data communication. It is the process by which data or information can be easily and conveniently exchanged from one place to another reliably. Communicating devices for data communication must consist of a combination of hardware and software. The functionality of a data communication system depends on three main features. 1. Delivery : The system must deliver data at the right end. 2. Accuracy : The system must deliver data properly. 3. Timelines : The system must deliver data on time.