This Cable Tester Is Designed To Troubleshoot Rj45 Lan Cables, Both Utp And Stp|It Not Only Tells You If The Cable Passes Or Fails The Test, It Indicates Which Pins Fail And Whether They Are Open, Shorted, Or Crossed|The Tester Has Two Basic Testing Modes: Auto And Step|In Auto Mode It Makes A Single Pass Over The Cable And Gives A Result