There's no turning back. This is the aspect that UnionPay and banks can't provide services, so the central bank approved some enterprises to participate in financial services, that is, third-party payment enterprises, believing in their service awareness. Errors like this can only be dealt with next time, and receipts should be checked on the spot to prevent mistakes. UnionPay pos machine, referred to as POS terminal for short, is a point-of-sale information management system with cash or barter offline cashier function. Its working principle is to dial the telephone line to send the information to the platform of UnionPay. After the platform recognizes the relevant information, it will send the deduction information to the issuing bank, and the issuing bank will send the information back to the platform of UnionPay after confirming it. After confirmation by UnionPay, the processed information will be sent to the front-end terminal, and the terminal will print the documents after receiving the confirmation information. Mobile POS terminals send and receive information through data signals based on the same principle. The communication fee is not much, and the fixed terminal communication fee is charged by the telecom company according to the local telephone standard. UnionPay pos machine has the functions of fund settlement, safety and convenience, and is well received by consumers.