1. Suitable for 40 pin GPIO interface, suitable for series motherboards 2. Using SC16s752 and SP3485 dual chip combination scheme, SPI can be converted to RS485, and the communication rate is up to 921600bps 3. Support manual or automatic sending and receiving of data, which can be set by dial switch 4. The onboard (transient voltage suppression tube) can effectively suppress the surge voltage and transient spike voltage in the circuit, and it is anti- Pattern and anti-static 5. The onboard self-recovery fuse and protection diode can stable output of current and voltage, prevent overcurrent and overvoltage, and improve impact resistance 6. Onboard power supply and serial port transceiver indicator light, easy to check the module power and communication status 7. Lead out the SPI control interface for easy access to the main control board such as for Serial port expansion chip: SC16IS752 Working voltage: 3.3V or 5V RS485 transceiver: SP3485 Communication interface: SPI Via diameter: 3.0mm Communication rate: 300-921600bps Colour:blue Material:PCBandmetal Size:56 x 65mm Package Contents: 1 x RS485 Expansion board module Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.