Abstract: Hook conditions of a handset of a telephone apparatus which includes a telephone apparatus base having an inside and an outside are sensed by providing a beam of radiation outside of that telephone apparatus base. The handset is placed in that beam of radiation outside the telephone apparatus base in an on-hook condition of that handset on the telephone apparatus base. An off-hook condition of the handset is signaled by removing that handset from that beam of radiation while removing such handset from the telephone apparatus base. A method of preventing eavesdropping through microphone and earphone of a handset of a telephone apparatus opens a circuit of either the microphone or the earphone and short-circuits either the earphone or the microphone, respectively while the handset is on-hook on a base of that telephone.

Abstract: A modular plug is locked in a modular receptacle by a frangible locking member disintegral from such modular plug. An internal first catch on that frangible locking member catches an inside of the modular receptacle. The internal first catch is rendered inaccessible from outside the modular receptacle when the frangible locking member and the modular plug are in place in that modular receptacle. A second catch on the frangible locking member detains the modular plug in the modular receptacle until the frangible locking member has been broken up. A device for locking a modular plug in a modular receptacle has a locking member disintegral from such modular plug and having a frangible head. A pair of spaced flexible prongs project from such head. A catch on each of such flexible prongs is spaced from the frangible head and a third or middle prong projects from the head between the pair of spaced flexible prongs.

Abstract: An emergency exit is provided through a revolving door, having leaves angularly spaced from each other and rotatable in an enclosure in an operating condition, by automatically aligning all of these leaves parallel to a line of exit traffic through the enclosure. The revolving door leaves may be so aligned by first biasing the leaves toward each other, but maintaining the leaves angularly spaced by releasable retention against the bias exerted by such biasing, and by thereafter releasing such retention in response to an emergency condition and aligning the leaves automatically by force of the bias.

Abstract: Shearing motion between first and second parts of an electromagnetic lock for maintaining a door shut are translated into a force tending to lift the second part away from the first part of the energized lock, and the shearing motion is countered by countering the latter force with the magnetic attraction between the first and second parts of the energized electromagnetic lock. The mechanical friction between the mutually attracted first and second lock parts is added to the full holding force between these parts, so that the holding power of the lock considerably exceeds the holding power generated by the magnetic field between the first and second parts alone.

Abstract: Disclosed audio signal recording methods and apparatus operate with a telephone set having a housing and a handset connected to a first modular jack in the housing via a handset cord having at an end thereof a first modular plug fitting into the first modular jack. For audio signal tapping purposes, there is provided a second modular plug fitting into the first modular jack, a second modular jack for receiving the first modular plug, and an electrical interconnection of the second modular jack with the second modular plug. The second modular plug is inserted into the first modular jack and the first modular plug into the second modular jack. Audio signals are tapped from the electrical interconnection of the second modular jack with the second modular plug and are recorded.

Abstract: Matching components of a magnetic locking assembly are magnetically attracted into mating relationship until a predetermined magnetic flux is established in one of the components. Such established predetermined flux is monitored to detect locking power diminutions between the locking assembly components. External magnetic fields applied to the locking assembly in an attempt to counterfeit the mentioned predetermined magnetic flux may be detected and indicated for security reasons.