COM port pinout usage
What is the pinout for my serial port? What pins do I need to connect for a loop back test? Pinout and diagram of DE9 connector (DB9 connector), commonly used for serial ports (RS-232). Learn more about serial communication from Serial Port Pinout Guide and find the difference between DB9 pinout and RS232 Null modem pinout. Set up custom serial port pinout and use RS232 loopback .
RS-232 is the single ended serial protocol and RS-485 and RS-422 are differential serial protocol. The pinout for RS-232, RS-422 and RS-485 is shown below figure.
