1. Tests shielded (STP) or unshielded (UTP) LAN cables 2. Automatically detect a good connections, opens, short, crossover. 3. The lights of the main tester will turn on sequentially from 1 to G. 4. Detachable remote tester, test remote cable up to 1000ft. in length. OFF/ON/S Switch ON - Is a normal test speed S - Slow down the speed of the flashing light Off - Is to turn off the tester Network Cable Tester for RJ45 Network Cable & RJ11 RJ12 Telephone cable RJ45 Cable Test: Please insert the network cable into both the socket of the main unit and a remote unit. If this cable is a good connection, The lights of both the main tester and remote unit will light up sequentially from 1 to 8, Namely, Main Tester: 1-2-3-4-5-6-7-8 Remote Tester: 1-2-3-4-5-6-7-8 Above is for Unshielded cable G light - Is for shielded cable, the lights will light up from 1 to G Namely, Main Tester: 1-2-3-4-5-6-7-8-G Remote Tester: 1-2-3-4-5-6-7-8-G Easy to Carry This compact cable tester is an easy-to-use tester that saves time and money on the job. The portable handheld design makes this easy to use. Even if the cable is pre-installed it can be tested with a detachable part. Error Free Operation Complete error-free operation with DC detecting anode and cathode determination, ringing signal detecting open, short, and cross circuit testing. Power Source: DC9V Battery Required (not included), But Does Not Work Under DC7V