Voltcraft lsg 3 test leads measurement device voltcraft tct 680 p the voltcraft lsg 3 is a practical detector for tracking and identifying lines and cables it can also test telephone and network cables coaxial 10 100 100 base t for correct wiring and continuity the lsg 3 uses a high frequency tone generator which modulates a hf signal on the test cable it also includes a highly sensitive inductive receiver which can detect cables up to 15cm inside a wall this allows you to track cabl