Find out what's going on with your LAN lines. This Ethernet cable tester allows you to see open circuits, shorts, crossed pairs, reversed pairs and split pairs in just a few seconds. It comes with a built in tone generator to send a signal from one end or point of your cable to another. Use this tone generator on cables that are already installed in walls or ceilings that you do not have access to with the single-tone or multi-tonal mode. The Hobbes LANTest PRO comes with one master unit and one remote unit. Both can be easily operated by a single person. The remote unit is designed to fit inside the master unit to prevent any loss or damage.