The data communication is in accordance with certain communication protocols, data transmission technology to pass data between two terminals of a means of communication and communication services. It can be realized computers and computer data transmission of information between computers and terminals and terminals and terminal. Is the third largest communications business after the telegraph and telephone services.
Data communication is different from the telegraph, telephone communications, it implements the main (terminal) - machine (computer) communication with the machine - machine communication, but also includes "(intelligent terminals) -" communication. Message in the data communications are in the form of binary data to the performance. Another feature of the data communication it is always associated with telematics, including scientific computer, process control, and generalized information processing information and pick up cable content.
The data communication system is a complete system consisting of computer, remote terminal and data circuits and related communications equipment. A remote information processing system or computer network must achieve two functions of data communications and information processing, information transmission services for the latter, while the latter is the application of the system on the basis of the former to provide services.
In order to achieve data communications, data transmission, data issued by the upcoming data sources in one place information transmitted through the transmission channel to another ground data receiving device. In order to improve transmission quality and reduce the error rate and transmission process effectively, according to the requirements of different applications require different types of error control, data link control procedures, and some of these procedures in line with international standards, some national standards, some companies developed. Open user interface is usually national or international standards to facilitate interconnection.