JMY601 series are RFID reader/writer module with UART serial ports. JMY601 has various functions and supports multi ISO/IEC standard of contactless card; the cards from different suppliers. The RF protocol is complex. But the designer combined some frequent used command of RF card and then user could operate the cards with full function by sending simple command to the module through UART interface. The module and antenna are integrated design. The impedance between RF module and antenna was tuned by impedance analyzer. And then the module has excellent performance and stability.