This is a stupid question.
I know when plug a cable into each end of the tester, if the light is on for each wire, that means the cable is good.
But how do you know which end of the cable is bad if the light is out. I want to test between the wall drop and the patch panel, assume the cable is good, Lets say I didnt install the wall drop correctly, how would I know from tester point of view? thx