When the credit card is consumed, the POS machine displays the card fraud and card swallowing.

If there is this prompt in the text message, it is that there is something wrong with the pos machine, or it is a capping machine or a modified machine. 2. If it is prompted by the pos machine, there is something wrong with the card or the card has been copied. Friendly reminder: frequent use of cards will help your reputation. Concept: POS(Point of sales), which means "point of sale" in Chinese, is called point of sale information management system. It is a terminal reader equipped with bar code or OCR code technology, which has the cash register function 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 1.POS system is to first create commodity data in computer files. Through the on-line structure of the computer cash register, the barcode on the goods can be directly read through the optical reading device on the cash register equipment (or the code can be directly input through the keyboard), and the information of the goods (unit price, department, discount ...) can be displayed immediately, which speeds up the cash register and is correct. 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.

2. The POS machine reads the magnetic stripe information on the cardholder's bank card through the card reader, the POS machine operator inputs the transaction amount, and the cardholder inputs the personal identification information (password). The POS machine sends the information to the issuing bank system through the UnionPay center to complete the online transaction, give the information of success or failure, and print the corresponding bill. The application of POS realizes the online consumption of credit cards, debit cards and other bank cards, ensures the safety, rapidity and accuracy of transactions, avoids complicated labor such as manual blacklist inquiry and bill pressing, and improves work efficiency. The design requirements of magnetic stripe card module meet the needs of three-track magnetic cards, that is, the module should be able to read magnetic cards with 1/2, 2/3 and 1/2/3 tracks.