I know I can use an HDMI source like a Raspberry Pi and a small screen for HDMI and could twist copper cable together and measure continuity through them to narrow down which is which but I’m wondering if there is an easier way. Maybe something I connect to either end?
I just stick a 9v battery on two wires on one end and then test for the voltage with a voltmeter on the other end. If I need to sort out multiple wires, I just feed different low voltages over different wires and test at the other end.
It’s always worked for me :). Wire is wire, as long as you don’t try to run higher wattage over it than it can handle.