MASTER UNLOCK CIRCUIT FOR A FEATURE TELEPHONE STATION INCLUDING A SIGNALING LOCK CIRCUIT

摘要

MASTER UNLOCK CIRCUIT FOR A FEATURE TELEPHONE STATION INCLUDING A SIGNALING LOCK CIRCUIT A circuit which unlocks the signaling circuit of a feature telephone station after it has been locked. A microprocessor disconnects a tone generator from an associated keypad upon detection of operation of a lock button. The microprocessor subsequently connects the tone generator to the keypad upon detection of operation of the lock button and a predetermined master unlock code provided via the keypad. The microprocessor also connects the tone generator to the keypad upon detection of operation of the lock button followed by simultaneous operation of a predetermined plurality of telephone feature buttons.