Based on for Pi40pin GPIO interface, suitable for Pi series motherboards Using the SC16IS752 and SP3232 dual chip combination scheme, which can realize the conversion of SPl to RS232, and the communication rate is as high as 921600bps Onboard (transient voltage suppression tube), which can effectively suppress the surge voltage and transient spike voltage in the circuit, and is anti- and anti-static Onboard power supply and serial port transceiver indicator light, easy to check the module power and communication status Lead out SPI control interface for easy access to main control boards such as for size: 55 x 21 x 15mm Material:ABS colour:blue Package Contents: 1 x Dual-channel Expansion Board 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.