sbrown:
I still don't quite understand how you where suggesting to incorporate output pins back on page 4 but I may continue to think about this in order to detect shorts and also be able to communicate which wire is discontinuous.(?) (Even if these things aren't necessary I'm just trying to learn as much as I can from this project.)
So rather than hook all the wires to a common ground on the far end, you connect a separate Arduino pin to each wire on the far end.
When the Arduino pin on the far end is in INPUT_PULLUP mode the input side of the wire will read high.
When the Arduino pin on the far end is in OUTPUT mode (which will default to LOW) the input side of the wire will read low.
If you set all the far end pins to INPUT_PULLUP and then set only 1 pin to OUTPUT, then only a single pin should read low.
If you read low on more than the expected pin you have a short.
If you don't read low on the expected pin, you have a broken wire.
You do this test for each wire.
This allows you test each wire for continuity or a short to any of the other wires.
The longest cable I have to test is about 20" or just over a 1+1/2 feet.
Should not have any issues. My concern was if you had cables longer than 25+ feet.
--- bill