Does anyone know how cable mappers are setup, for example I have one for cat 5 that has a 1,2,3,4 end that you hook up and when the tester is hooked up to the other end it tells you what number you are hooked up to. I was thinking maybe each one has certain resistor but I dident want to mess with it to find out since it was a little pricey
I think most of them work by sending a tone down each wire.
well the transmit end is not powered, wouldent it need a battery in it if it was sending a tone?
I had one ages ago. Mine used some diodes and an OR solution complete a circuit path. Not really that complex. If you work with LED's... built in diodes... think about it this way...
If it's not LOGIC "1" or somewhere close to 5 volts... it can be supplying a ground path to complete the circuit.
8 wires, four twisted pair circuits and polarity matters.
The testers I had access to only did continuity tests, so I took a decade counter, rigged it to step through the four pairs and had LED indicators to show that on the transmitter. The other end (receiver) had four two-color Green/Orange leds to complete each twisted pair circuit, which would flash in the same sequence and green if the connections were correct. Out of sequence, Orange or unlit showed you'd mixed the A/B spec, reversed, cross connected or messed up the punchdown. Not sure if that's what you're getting at, but an Arduino could easily replace the decade counter discrete circuit.