Not only the Bank of Communications credit card can brush the POS machine by hand, but other banks can also brush the POS machine by hand. However, the risk control of Bank of Communications is strict, so cardholders must pay attention to the operation when spending and maintaining their cards. Most importantly, don't brush the POS machine by hand at a low rate. Most hand-brush POS machines below 0.6% in the market have security risks, and blindly coveting low rates is not worth the candle.
Internal analysis
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 of all, the POS will first detect the /RING and /PHONE signals to determine whether the voltage on the telephone line can be used, and then dial the tone when the switch returns.
POS dialing, sending light flashing, starting dialing, confirming handshake between switch and POS through communication protocol, etc. , and then start the data exchange of POS, and send and receive signals through MODEM circuit; Hang up when finished and end the process.