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.
Communication interface circuit usually consists of RS232 interface, PINPAD interface, IRDA interface and RS485 interface circuit. RS232 interface is usually the download port of POS program, PINPAD interface is usually the interface between host and password keyboard, and IRDA interface is usually the infrared communication interface between mobile phone and landline. An interface signal usually consists of a sending signal, a receiving signal and a power signal.
The modem board consists of central processing module, storage module, modem module and telephone line interface. First, the POS will detect the /RING and /PHONE signals to determine whether the voltage on the telephone line can be used. The switch is reset, you can dial, and the sending light flashes to start dialing. The communication protocol determines the handshake confirmation between the switch and the POS, and then the data exchange of the POS will start, and the signal will be sent and received through the modem circuit. Hang up when finished and end the process.