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WirePulser: A DIY Wire Locating Tool - element14 Community
How to Make a working wire tracer with spare parts « Hacks, Mods & Circuitry :: Gadget Hacks
Cable Finder Tone Generator Probe Tracer Wire Tracker Cable Circuit Tester Features Alligator Clips RJ11 Plug Finding Tool : Amazon.sg: DIY & Tools
Proster Network Cable Tester Cable Tracer with Battery Earphone Sensitive Wire Tracker Telephone Cable Tester Wire Tracer for LAN Ethernet RJ45 RJ11 : Amazon.co.uk: DIY & Tools
signal - How does a cable tone-and-probe kit work? - Electrical Engineering Stack Exchange