Ideal for programmers, hardware engineers and DIY User. Compared to other USB to TTL UART adapters, this adapter not only supports 3.3V and 5V logic levels, but also adds support for 1.8V and 2.5V logic levels.At the same time it is equipped with a protective plastic case, this protective plastic case can effectively prevent static interference and various short circuits. Specification: Model: SH-U09C5 Main chip: FTDI FT232RL Pin Definition: CTS,RTS,RXD,TXD,GND,VCC,DSR,R1,DCD,DTR,RESET Output VCC: 1.8V/2.5V/3.3V/5V TTL Level: 1.8V/2.5V/3.3V/5V USB interface: 2.0 The maximum speed: 3Mbps About indicator LED: PWM LED:Power Indicator RXD LED:The data transmission indicator flashes when there is data from the USB port. TXD LED:The data receiving indicator flashes when the USB port receives data. List of supported systems 1,Windows xp,7,8,10 2,Ubuntu 11.10, kernel 3.0.0-19 3,Mac OS X 10.3 to 10.8 (32 &64 bit) 4,Mac OS X 10.9 and above(64 bit) You can download the driver directly from FTDI's website Packing list: 1 X FTDI FT232RL SH-U09C5 USB to TTL Adapter with a plastic case 1 X User Manual 1 X 4 PIN DuPont cable WARRANTY: DSD TECH offers a 1-year warranty and lifetime technical support for this USB-to-TTL adapter?If you meet any question, Please contact us, We will fix your issue within 24 hours.