Aleratec 250365 Raspberry Pi Add On Expansion Board GPIO TX & RX to DB9M RS232 Serial Host Adapter Connect Raspberry Pi TX &#47; RX on GPIO header to a DB9M RS232 Serial port Level shifter &#177;3.3VDC serial transmit &#40;TX&#41; and receive &#40;RX&#41; from the UART on the Ideal to connect serial communication RS232 peripherals&#44; industrial equipment &#40;such as PLCs&#41;&#44; Supports baud rate up to 230 Kbps Supports VCC input 2.7V ~ 5.25V