Test of double-twisted cables: Switch on the power. (S is slow automatic grade, Mis manual.) Put cables into both main tester and remote tester. The lights of the main tester will turn on sequently form 1 to G.
Main tester: 1-2-3-4-5-6-7-8-G
Remote tester: 1-4-3-2-5-6-7-8-G
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 will not turn on. 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.