Wire chief test set

A specialized piece of diagnostic equipment used by a telephone exchange's "wire chief" (the technical supervisor) or a maintenance technician to troubleshoot telephone lines. It was essentially the ultimate "command center" diagnostic tool for keeping early local telephone networks up and running. When a subscriber reported a dead or noisy line, the wire chief would use this board to run a battery of tests without leaving the central office. It allowed them to find: 1) "Opens": Broken wires or bad splices. 2) "Shorts": Wires touching each other. 3) "Grounds": A wire touching a tree branch or a wet pole, causing current to leak into the earth. 4) Crosses: Telephone lines accidentally touching other power or telegraph lines.