The excellent performance of ft4232hl is very suitable for industrial occasions with high requirements. It realizes simultaneous communication of a single USB and four UART serial ports, which are and of each other. The computer displays four COM ports and provides a communication rate limited to 12mbps. Instructions:Use USB cable to connect computer and micro-usb interface on board. After computer installs driver, you can see that there are four COM ports. Use short-circuit cap to select desired voltage of VCC / TX / RX on TTL power selection interface to output corresponding voltage. The smallest value of COM port corresponds to first TTL interface, and largest value corresponds to fourth TTL interface (the value of COM port is not fixed). For simple test, you can short-circuit TX / Rx, and then use upper computer to send information to see if there is data . Colour:Green Material:PC Package Contents: 1 x Converter Module(Due to different product batches, the appearance , which does not affect use) Only above package content, other products are not included. Note: Light reflection and different displays may cause color of item in picture a little different from real thing. The measurement allowed error is +/- 1-3cm.