What Is data communication

Data communication is a communication mode and communication service that transmits information between two terminals according to a certain communication protocol. It can realize the data information transmission between computer and computer, computer and terminal, and terminal and terminal. It is the third largest communication business after telegraph and telephone service.

Data communication is different from telegraph and telephone communication, it realizes mainly "(through terminal)-Machine (computer)" Communication and "machine-machine" communication, but also includes "person (through intelligent terminal)-person" communication. The information transmitted in the data communication is expressed in binary form. Another characteristic of data communication is that it is always connected with remote information processing, and it is a generalized information processing system including scientific computer, process control, information picking and so on.

The data communication system is a complete system composed of computer, remote terminal, digital circuit and related communication equipment. Any remote information processing system or computer network must realize the functions of data communication and information processing, and the latter should be used to provide the latter with the service of the former, which is to realize the application of the system based on the service provided.

In order to realize data communication, it is necessary to carry out data transmission, which will be transmitted to another data receiving device through transmission channel. In order to improve the transmission quality, reduce the error rate, and make the transmission process effective, the system according to different application requirements, the different types of error control data Link control procedures, which are in line with international standards, some national standards, but also some companies to make their own. But the open user interface is usually the adoption of national standards or international standards, in order to facilitate interconnection and interoperability.

There are two main ways of data exchange: circuit switching and packet switching, in which packet switching is more widely used in real data networks. In a data network with packet switching, in addition to the various functions required by data transmission and link control procedures between neighboring switching nodes, packet storage and forwarding, routing, flow control, congestion control, user network connection and network maintenance are still required on each switching node. Management and other aspects of the work. Communication protocols are the rules and conventions that must be followed in order to communicate accurately and effectively. It can be divided into two types, one is related to the data communication network (from the composition of computer networks, sometimes referred to as communication subnets), including the network between nodes and nodes, as well as network and end of the protocol between the system. The other is the protocol between the end system and the end system, which is necessary for realizing the interoperability between the end systems and achieving certain application purposes on the basis of the functions implemented in the previous protocols.

As a kind of communication data communications, it provides services for realizing the broad sense of remote information processing. Typical applications include: File transfer, e-mail, voice mail, visual text, directory inquiries, information retrieval, intelligent user telegrams and telemetry, remote control and so on.