Suitable for USB cable, USB print cable, telephone wire, power cable, RJ45 network cable testing, etc; Usage: Connect the network cables into main tester and remote tester, switch on the power (ON is for quick testing, S is for slow testing), Lights will turn on sequently from 1 to 8, the cable are in normal condition; If any light turns on unsequently, the cables are in wrong connection; If one light is not on, the related cable is not connected; If all light are not on, half of the cables are not connected or with other problems.