If several cables are not connected, several lights will 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. 2and NO. 4, then displays on: Main tester: -4-5-6-7-8-G Remote tester: 1-4-3-2-5-6-7-8-G 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 patch panels or wall plate outlels, two cables which can match each other (RJ45) will be connected to the tester. If cables of the same axes, BNC turns on when the cable works. size:about 103x97x27mm Material:ABS colour:Black Package Contents: 1 x M469D RJ45 Cable lan tester Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. of double-twisted cables: Switch on the power. (S is slow automatic grade, manual.) Put cables into both main tester and remote tester. The lights of the main tester will turn on sequently form 1 to G. Remote tester: -4-5-6-7-8-G RJ45 -4-5-6 RJ11 Following are abnormal connections: Main tester: -4-5-6-7-8-G If one cable, for example cable NO.3 is open circuited, the two NO.3 lights of the main tseter and remote tester will not turn on.