POS(Point of sales), which means "point of sale" in Chinese, is a terminal reader equipped with barcode or OCR code technology, and has the function of teller of cash or barter bank. Its main task is to provide data services and management functions for commodity and media transactions, and to carry out non-cash settlement. POS is a multifunctional terminal. It can be installed in special merchants and acceptance outlets of credit cards, and connected with computers to realize automatic transfer of electronic funds. It has the functions of supporting consumption, pre-authorization, balance inquiry and transfer, and is safe, fast and reliable to use. It is difficult to obtain basic business information for bulk transactions, and the introduction of POS system is mainly to solve the blind spot of retail information management. An important part of chain branch management information system.

The basic principle of POS system is to create commodity data in a computer file, directly read the barcode on the commodity through the online structure of the computer cash register and the optical reading device on the cash register equipment (or directly input the code through the keyboard), and then display the commodity information (unit price, department, discount ...) immediately, so as to speed up the cash register and make corrections. The detailed information of each commodity sale (price, department, time period and customer level) is automatically recorded and then sent back to the computer by the online framework. Through computer calculation and processing, various sales statistics and analysis information can be generated as the basis for management.