Phone jack testing

There shouldn't be any voltage, but things can get miswired. Check for voltage (AC then DC) between all wire pairs at the phone drop into the house, and between each and a good earth ground.

If you don't find any voltage, you can do a continuity test on the jacks: go around to all jacks, and measure the resistance. They should all read open, if no phone equipment is attached.

If you get a low resistance, something is causing a short, and you'll have to disconnect each wire run at the breakout box to find which circuit the short is on.

Then, short the terminals on one jack, and go around to all the others to measure for a low resistance. If any jack still reads open, it's not connected.

HTH

Testing for what? Check for voltage first, then open ohm pairs then individually twist the remote end pair together and ohm again.