Bidirectional communication connecting line for cash register and payment terminal

The utility model relates to a bidirectional communication connecting line for a cash register and a payment terminal. Comprising a main control module, the main control module is provided with at least two interfaces, the main control module can analyze transaction information sent by a cash register and obtain corresponding transaction amount, the transaction amount is transmitted to a payment terminal through the other end, and the payment terminal is controlled to carry out transaction through a payment channel of the payment terminal. The main control module adopts two S31 chips, the two S31 chips exchange data through serial port communication, one S31 chip is connected with a cash register, the other S31 chip is connected with a payment terminal, circuits formed by the two S31 chips are consistent and are each composed of a crystal oscillator circuit and a bypass capacitor, the crystal oscillator circuit is used for providing hour hand signals for a system, the bypass capacitor is used for filtering ou