The “Linascope” fault locator

The inspection of circuits by pulse reflection methods is well known to communications engineers. In particular this technique has been used in inspecting high-frequency coaxial telephone and television lines. The “Linascope” is an electronic instrument for locating faults on open-wire telephone and transmission lines. The unit generates repetitively a short duration pulse which is fed to the circuit under test. The pulse travels along the line at a speed nearly equal to that of light (186 miles per millisecond). Echoes arise from faults, junctions, terminations, and other impedance irregularities, and return to the Linascope terminals at the same speed.