JMY680 series are RFID reader/writer module with IIC or UART serial ports. JMY680 has various functions and supports multi ISO/IEC standard of contactless IC card; the cards from different suppliers. The designer combined some frequent used command of RF IC card and then user could operate the cards with full function by sending simple command to the module through IIC or UART interface. The module and antenna are integrated design. And the impedance between RF module and antenna was tuned by impedance analyzer. So the module has excellent performance and stability.