Nexxt Solution Lan cable testers use an LED display to show the condition of patch cables and installed cabling. It tests for faults such as open wires, shorts, reversed pairs, crossed pairs, split pairs, and mis-wiring in seconds. With the push of a button, the cable tester will automatically scan all wires and pairs to determine any existent faults. The network cable tester includes one master and one remote unit. The remote unit is designed to slip into the master unit to prevent damage and for easy portability.