This instrument is a multifunctional handheld cable testing tool. Work perfect when RJ11 RJ45 cable is on power. It has a wide application with reinforced cable types and multiple functions. It is a necessary testing tool for telecommunication engineering, wiring engineering, and network maintenance person, Wire tracing Trace RJ11, RJ45, cables or other metal wire (via adapter). Easy and fast to locate the breakpoint without opening the co, Network cable collation: judge short-circuits, breaking circuit, open circuit and crossing, Status of telephone line checking: test the working status of telephone line (idle, ringing, and off-hook) and judge TIP and RING line, Check wire continuity. Handheld Telephone Wire Tracker Tracer Toner Ethernet Lan Network Cable Tester Detector Line Finder , Wire Tracker Tracer Ethernet Lan Network Cable Tester , Multifunctional Cable Tracker RJ11 RJ45 Wire Tracker Ethernet Tracker Finder Tester for Networking Cable Testing Tool Telephone Phone Wire Line Tester Continuity Checking Electric Wire Finder Tracker Digital Multimeter Blue 2000 Counts