While there are plenty of other wire map testers on the market this is the one that Network Twenty-One Inc. relies upon, for good reason, this wire map tester not only identifies opens, shorts, grounds, reversed pairs and shield breaks. It also gives you the distance to the fault. In the past we always had to assume the trouble was at one end, or the other. But what about when your cable has been chewed into by a rodent at 120' from the TR, above the ceiling tiles. That is a tough problem to find. Click here to watch a video on how to use this test equipment.