Built-in a new and original FTDI IC device 'FT232RL', which handles all the USB signalling and protocols. TTL levels of +5V and +3.3V adjustable design, and draws power directly from your PC/laptop via the USB connection, no need for an external power adapter Provides access to UART Transmit (Tx), Receive (Rx), RTS#, CTS#, VCC and GND connections; POW(power), RXD/TXD transceiver communication LED indicator design, which can show serial adapter status and data activity at a glance Windows 8 and above OS, Linux and Mac OS will install FTDI driver automatically, but NOT compatible with Chrome OS. For details of OS compatibility and installation guidance, please scroll down this page and take a look at 'Product description'