Traces, tones, tests and easier than Fluke. In one step I was able to unplug the cable, plug it in and see if there was a connection to all pairs. Simple LED indicators for each wire, and if one of them got disconnected, I knew immediately if there was a problem without having to switch the signal to another mode (especially when the signal was sent from several hundred meters away ). below, where each floor has two ordinary floor stairs (aircraft repair station).