Device for sequentially altering a communication line for remote diagnostic checks

摘要

A network termination unit for connection to a telephone line at a predetermined demarcation point thereof for sequentially simulating a plurality of fault conditions to allow a diagnostic routine to be performed on the telephone line at a remote location from the demarcation point. The network termination unit includes a plurality of semi-conductor switches electrically connected to conductors of the telephone line to establish a network of electrical paths capable of altering the electrical condition of the telephone line when caused to assume a state of conduction. A logic module causes the switches to assume either a closed or an opened condition in accordance with a predetermined sequence established by a hard-wired program.