The standard way to connect a serial port (RS232) to an Arduino (or any 0V/5V based serial interface) is to use a dedicated IC like MAX232A. With this IC, you don't need a 9V battery like with my ...

For the challenge, I wanted to send data from my computer's real serial port (RS232 9-pin connector). For that, I created an adaptor circuit because the voltages on a computer serial port are ...

Arduino and PLCs Hook Up Via RS232 and Modbus There is a thriving online developer community using RS232, Arduinos, and PLCs to build industrial and home automation systems on the familiar serial ...

From there, and with the knowledge that most POS terminals use RS232 to communicate, he was able to zero in on the Rx and Tx pins on the on-board microcontroller and interface them with an Arduino.

Balluff has added this neatly-packaged bi-directional interface for connecting RS232 cables to IO-Link (IEC 61131-9) cables. “The converter lets you connect devices like barcode scanners, printers or ...