US 5,592,529 AGranted

Telephone inadvertent off-hook condition detector

AssigneeInternational Business Machines Corporation

InventorRalph Linsker

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Abstract

An inadvertent-off-hook-condition detecting apparatus for use with a telephone connected to a telephone system is described. The telephone has a hookswitch which connects the voice network of the telephone system across the input lines to the telephone when the hookswitch is in an off-hook position, and which disconnects the voice network from the telephone input lines when the hookswitch is in an on-hook position. The inadvertent-off-hook-condition detecting apparatus has detecting circuit coupled to the telephone for detecting a prespecified signal indicating that the local or remote party wishes to continue the telephone conversation; a timer coupled to the detecting circuit and to the telephone for determining whether the elapsed time since the most recent of the events comprising (1) existence of an on-hook condition and (2) detection of the prespecified signal, is in excess of a prespecified time interval; and an output generator coupled to the timer for producing an output signal indicative of whether the prespecified time interval has been exceeded.

Claims19

Dependent claims

An apparatus for use with a telephone connected to a telephone system, said telephone of said telephone system having means for a user to generate a user generated reset signal, comprising:

said telephone having a hook status selected from a group consisting of on-hook and off-hook,
a detector, having means for coupling to said telephone, for detecting said user generated reset signal;
an indicator of said hook status having means for coupling to said telephone, for producing a hook signal;
a timer, having means for coupling to said telephone, said timer producing a timer signal if and only if said telephone is continuously off-hook for greater than an off-hook time and said user generated reset signal is not detected by said detector within a reset time;
an output signal generator coupled to said timer for producing an output signal;
an auxiliary control for providing said user generated reset signal;
an alarm coupled to said timer;
if said telephone is continuously off hook for greater than said off-hook time and said reset signal is not received within said reset time said telephone is determined to be inadvertently off-hook;
a re-hook means to place said telephone in an on-hook status;
an alert means coupled to said timer for generating an alert signal and wherein if said timer produces said timer signal, said alert means generates an alert signal;
combining means coupled to said detector, said indicator and said timer.

8 more elements

Dependencies are inferred from the claim text.