5V FTDI Basic USB to RS232 Serial UART Converter - Arduino Compatible - by UPGRADE INDUSTRIES FT232RL chip (28pin TSSOP) (RS232 Converter) Selectable voltage - 3.3V or 5.0V LEDs that blink for Transmit and Receive USB Bus Powered (up to 500 mA when configured using utility at FTDI's website) User programmable flash memory, GPIO control and pin functionality