Not sure what's wrong with your network? Before you buy an expensive replacement router or cable modem, test your cables! If the wires are broken (and you know how those cables get snaked around the house) the tester will detect it. If you make your own patch cables and want to test that the wires are correctly assigned, then you need this! Test your twisted pair, Straight, Crossover, Cat 5 / Cat 5e / Cat 6 / UTP cables with RJ-11 or RJ-45 connectors. Insert the battery, turn on the tester, and connect one end of the cable to the Master side and the other end to the Remote side. The lights indicate problems (if any) with wires in the cables. A very useful item for the networking enthusiast!