Abstract: A manually assisted lockout relay circuit is used in a telephone switching facility to disconnect and isolate an offending subscriber's telephone line to prevent it from capturing and holding central exchange equipments that are commonly accessible and needed by a plurality of other subscribers. A central office technician, through use of the master test frame, determines that the offending subscriber has removed the telephone handset from its hook or cradle and has not made an attempt to complete a call. An offending subscriber, for whatever reason, persists for long periods of time, and on repeated occasions, in leaving his handset off hook. In such instances the technician energizes the lockout relay, by application of central office high voltage, to isolate the offending subscriber's line from the system. Replacement of the handset by the offending subscriber resets the circuit for normal operation. Inadvertent lockout in normal operation is prevented by a zener diode in series with the lockout relay.