US 4,358,639 AGranted

Permanent signal holding module

OwnerJoseph P. Morininventor

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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. The lockout circuit is in modular form with plug-in and wired connections. A specific design has been made for use with the popular #5 crossbar exchange offices.

Claims10

Dependent claims

A method of selectively holding an improperly used subscriber's telephone line from apparatus internal of a central exchange office which comprises the steps of:

a. recording detections of off the hook incidents, over a period of time, for establishing an historical account that a specific subscriber is a habitual offender in the improper use of the telephone set and system, wherein a detection of an improper use is determined by monitor scanning the multiplicity of subscribers' lines within a permanent signal holding (PSH) trunk of a central exchange for continued presence of continuity through individual subscriber lines, each subscriber line comprising a pair of tip and ring conductors;
b. installing a (PSH) module as an add-on modification to central office apparatus at the line link conductors of said subscriber known to be a habitual offender, said PSH module installed bridging said subscriber's line link tip and ring conductors, said PSH module further interposed in series with said ring conductor, said PSH module for holding off the hook offenses of said subscriber from using central office internal apparatus;
c. detecting by said monitor scanning of pairs of tip and ring conductors of known habitual offenders whose lines are equipped with said PSH modules to determine that said subscriber's handset is currently off the hook, no call was attempted, and said subscriber is improperly holding central office apparatus;
d. applying electrical energy by a temporary means to a normally isolated winding of a lockout relay assembled within said PSH module to energise said relay, said relay having multiple switching contacts, with at least one said switching contact set, normaly closed, in series with said ring conductor;
e. latching said lockout relay to the energised state by flow of electrical current from a negative battery source through a series circuit comprising a resistor, said isolated winding and a set of made contacts of said lockout relay, thence through said offending subscriber's line, telephone set, and contacts of a hold magnet relay to a central office grounded return for said battery source;
f. disconnecting said offending subscriber's telephone line by opening said switching contacts of said lockout relay normally closed in series with said ring conductor so that all held apparatus internal of said central exchange office are released for the duration of the off hook state of said subscriber's telephone handset;
and
g. restoring said subscriber's line to normal operation automatically after proper replacement of said subscriber's telephone handset to its holding hook or cradle, thereby terminating the offense, said replacement of the handset interrupting the flow of electrical current from said negative battery source through said winding of the lockout relay.

5 more elements

A semi-automatic arrangement for a telephone communications system to permanently hold a subscriber's line from internal apparatus of a central exchange facility for the duration of an off hook condition of a subscriber's telephone handset, said arrangement comprising:

a. central exchange apparatus comprising conductors and switching devices for routing and connecting a multiplicity of subscribers' lines from a line link frame to a master test frame, said conductors and switching devices further comprising tip, ring and supervisory or sleeve channels;
b. said master test frame comprising means for support of manual detection and determination of a handset off the hook condition on any selected subscriber's line;
c. said master test frame further comprising means for temporary manual application of electrical energy via said tip channel to said line link frame for the disconnection and lockout of a selected subscriber's line;
d. a PSH module responsive to said temporary manual application of electrical energy via said tip channel to said line link frame comprising switching means for disconnecting a selected subscriber's line from said internal apparatus of a central exchange, switching means for opening a hold magnet lead and placing ground potential on a line hold (LH) lead so as to make said selected subscriber's line appear busy to incoming calls from other subscribers addressed to said selected subscriber's line, and switching means for latching up said module in its disconnect mode without sustained application of electrical energy via said tip channel for the duration of said off hook condition of said subscriber's handset, said module automatically responsive to proper replacement of said subscriber's handset to its supporting hook or cradle, so as to restore said selected subscriber's line to normal operation;
and
e. there being a technician in attendance at said central exchange, for scanning said subscribers' lines, detecting and determing specific off hook offenses, deciding on the necessity for corrective action, and for applying temporary electrical energy to said PSH module to disconnect and lockout a selected offending subscriber's line, said technician using supportive means of said master test frame.

3 more elements

Dependencies are inferred from the claim text.