Their onboard LEDs are connected to pin D13, and their serial RX/TX pins are on pins D0 and D1, respectively. Additionally, the Nano and ... like the Arduino's built-in examples.

The electronics for this build include a printed circuit board that serves to break out the connections on an Arduino nano to a dozen ... of screw terminals to connect everything together.

Although a “CommsLink” module providing an RS-232 port was available back in the day, it’s become hard to find, inspiring [James] to design a completely new module based on an Arduino Nano.