Simple TDR

I have a handful of RJ45 (ethernet wires) that are electrically questionable.  Rather than plugging each between a network device and an ethernet switch, I thought it might be better if use software to test the continuity for each of the wires.

I selected an unused Arduino for the hardware that had 16 free analog and/or digital pins free.  (Yes you can run Digital over Analog Arduino pins).  I wired up the first RJ45 jack to pins 2-9 and the second RJ45 jack to pins A0-A7.  If your Arduino doesn't have those pins, you can change the PORTS definition in the source code.

I ended up calling it simpletdr.  (It isn't actually a time domain reflectometer, its more of a high speed continuity checker, but if you remove the delay(1) in the code it will associate pairs instead of individual wires instead of just checking DC continuity).

You can find the code here on GitHub.