Specification Brand : JESSINIE BulletPoint1 : The FT4232HL performance is very suitable for high demand industrial applications, achieving simultaneous communication through a single USB expansion of four UART serial ports, independent and not affecting each other. The computer displays four COM ports and provides a communication rate limit of up to 12Mbps. BulletPoint2 : Fireproof and flame retardant, convenient for maintenance, high temperature resistance, and safe quality BulletPoint3 : DC5.5-2.1 interface can provide high current to power external devices BulletPoint4 : VCC, TX, and RX can all be switched to 5V/3.3/2.5V/1.8V BulletPoint5 : The four serial ports use the XH2.54 interface, and all four UARTs have TX/RX indicator lights to display status. CompatibleDevices : Personal Computer, Laptop HardwareInterface : usb ItemName : JESSINIE FT4232-4TTL USB to 4-Way TTL Module UART Serial Port Module LED Indicator Micro USB COM Interface 12Mbps FT4232HL 5V 3.3V 2.5V 1.8V ItemPackageDimensions_Height : 0.7 inches ItemPackageDimensions_Length : 7.08 inches ItemPackageDimensions_Width : 4.72 inches ItemPackageQuantity : 1 ItemTypeKeyword : computer-cable-serial-adapters Manufacturer : JESSINIE ModelNumber : FT4232-4TTL NumberOfItems : 1 OperatingSystem : Windows, macOS, Linux ProductDescription : Instructions for use 1. Use a USB cable to connect the computer to the MICROUSB interface on the board. After installing the driver on the computer, four COM ports can be seen. Use a short-circuit cap to select the desired voltage of VCC/TX/RX on the TTL power selection interface to output the corresponding voltage. 2.The lowest value of the COM port corresponds to the first TTL interface, while the highest value corresponds to the fourth TTL interface (the COM port value is not fixed). 3. For simple testing, you can short circuit TX/RX and then use the upper computer to send information to see if there is any data echo.