Following are abnormal connections: If one cable, for example cable NO.3 is open circuited, the two NO.3 lights of the main tseter and remote tester not turn on. If several cables are not connected, several lights not turn on respectively. If less than two cables are conntected, none of the lights is on. If two ends of a cable is disordered, for example NO. 2 and NO. 4, then displays on: Main tester: -4-5-6-7-8-G // Remote tester: 1-4-3-2-5-6-7-8-G This model adopt automatic scan model, which can get a test result. RJ 45 Network Cable Tester tests double-twisted cables 1, 2, 3, 4, 5, 6, 7, 8 and Ground. Compact and light weight network cable tester, useful for home and outside use.The tester has a detachable section making it perfect for testing cable runs in different locations. Designed for test the wire circuit state of network cable, telephone cable, such as open, short, crossing, etc. Ethernet cables and RJ 45/RJ11 cables. With this network cable tester, you can judge wrong connection, short circuit and open circuit. If two cables are short circuited, neither of the corresponding lights is on of the remote tester while main tester remains unchanged. If three cables, including three, are short circuited, none of the corresponding liaghts is on. If test patch panels or wall plate outlels, two cables which can match each other (RJ 45) be connected to the tester. If test cables of the same axes, BNC turns on when the cable works., Weight: 0.24691773344 Pounds, Manufacturer: Aboiled