Please Note: This cable tester can not test electrified product. Battery is advised to change if any weak light appears. Test can not be done while RJ45 RJ11 copper screezers are not pressed. Any disobeys may lead to a permanent damage of the end. Please use quality tools to press the cables. How to Use: 1. Install a 9V battery, turn on the power of the network cable tester, and check if there is electricity; 2. When the network cable tester is measuring, first turn off the power switch. You need to connect both ends of a network cable, one end to the network cable interface of the tester host, and the other end to the network cable interface of the tester's auxiliary machine. Then turn on the power on the host and watch the display status of the test light; 3. Carefully observe whether the numbers on the two rows of display lights of the host and the slave are displayed symmetrically at the same time: if the display is symmetrical, it means that the network cable is good, if the display is asymmetrical or the individual lights are off, it means that the network cable is disconnected or the wire cores are arranged incorrectly when the network cable is made. Battery Needed Model:6F22 9V 25MA Cable Type: RJ11 Telephone cable and RJ45 LAN cable. Package:1pcs Network Cable Tester. Battery use 6F22 DC 9V 25MA (NOT INCLUDED).