Electronic telephone call restricting device

Claim 2

A circuit for restricting use of a telephone including telephone signal conducting means, first and second circuit means, and time delayed telephone circuit disabling means; said first circuit means being connected to said conducting means and responsive to a first dialed digit dial signal carried by said conducting means to connect said conducting means to said second circuit means and to activate said time delayed telephone circuit disabling means; said disabling means being connected to said signal conducting means and being adapted to operate to prevent conduction of signals by said conduction means upon lapse of a delay interval following activation thereof; said second circuit means being adapted to be responsive within said delay interval to said first dialed digit dial signal when said dial signal is that of a designated digit to prevent operation of said disabling means.

Claim 3

The circuit of claim 1 wherein said signal conducting means includes voltage regulator means adapted to provide circuit operating voltage across said signal conducting means; and, wherein said first circuit means is operable to apply said voltage to said telephone circuit disabling means for operating said telephone circuit disabling means.

Claim 4

The circuit of claim 1 wherein said signal conducting means includes first and second conductors, said first conductor including voltage regulator means adapted to provide a circuit operating voltage thereacross; and, wherein said first circuit means is adapted to be responsive to said first dial signal to apply said voltage to said disabling means and to said second circuit means.

Claim 5

The circuit of claim 3 wherein said first circuit means includes a latch circuit adapted to be responsive to a first dial signal pulse in said conducting means to connect said second circuit means to said conducting means and to activate said time delayed circuit disabling means; and, wherein said second circuit means includes a latch circuit adapted to be responsive to a dial signal pulse in said conducting means immediately following said first pulse to deactivate said telephone circuit disabling means.

Claim 6

The circuit of claim 3 wherein said first circuit means includes a first latch circuit, first latch circuit control means and a pass band filter, said control means being connected to said conduction means through said pass band filter, said latch circuit being adapted to be responsive to said first dial signal carried by said conducting means within the pass band frequency of said pass band filter to connect said conducting means to said second circuit means and to activate said telephone circuit disabling means; and, wherein said second circuit means comprises a second latch circuit, second latch circuit control means and a band reject filter, said second latch circuit control means being connected to said conduction means through said band reject filter, said band reject filter being adapted to block dial signals of frequencies other than said designated digit, said second latch circuit adapted to be responsive to said first dial signal when of a frequency of a designated digit to deactivate said telephone circuit disabling means within said delay interval.

Claim 7

A circuit adapted to prevent use of a telephone when the first dialed digit of a dialed number is other than a designated digit comprising: signal conducting means adapted to carry the dial signal of a first dialed digit; first circuit means connected to said conducting means; second circuit means connected to said first circuit means; and, time delayed circuit disabling means connected to said first circuit means and to said conducting means, said time delayed circuit disabling means being adapted to be operable to prevent further conduction of signals by said conducting means upon lapse of a delay interval following the activation thereof; said first circuit means being responsive to an initial portion of said first dial signal carried by said conducting means to connect said second circuit means to said conducting means and to activate said time delayed circuit disabling means; said second circuit means being adapted to be responsive to a subsequent portion of said dial signal occurring within said delay interval when said dial signal is that of a designated digit to prevent operation of said circuit disabling means and thereby avoid termination of conduction of signals by said conducting means.

Claim 8

A circuit adapted to prevent use of a telephone when the first dialed digit of a dialed number is other than a designated digit comprising: signal conducting means adapted to carry the dial signal of a first dialed digit; first circuit means connected to said conducting means; second circuit means connected to said first circuit means; and, time delayed circuit disabling means connected to said first circuit means and to said conducting means, said time delayed circuit disabling means being adapted to be operable to prevent further conduction of signals by said conducting means upon lapse of a delay interval following the activation thereof; said first circuit means being responsive to an initial portion of said first dial signal carried by said conducting means to connect said second circuit means to said conducting means and to activate said time delayed circuit disabling means; said second circuit means being adapted to be responsive to a subsequent portion of said dial signal occurring within said delay interval when said dial signal is that of a designated digit to prevent operation of said circuit disabling means and thereby avoid termination of conduction of signals by said conducting means.

Claim 9

A circuit for restricting use of a telephone comprising: first and second telephone signal conductors; voltage regulator means in said first conductor adapted to provide circuit operating voltage Thereacross; first and second latch circuits, said latch circuits including conductor means, conductor switching means and switching control means, said switching control means being adapted to operate said conductor switching means to control conduction of said conductor means and said conductor means being connected in series across said voltage regulator means; and, a time delayed circuit disabling means including means to effectively short circuit said first telephone signal conductor to second telephone signal conductor and delay means connected to said first latch circuit conductor means adapted to provide a delay interval between operation of said first latch circuit and operation of said short circuiting means, said first latch circuit being adapted to operate in response to an initial pulse in a dial signal to provide a conductive path between second latch circuit and said first conductor and to apply said voltage across said disabling circuit means, said second latch circuit adapted to operate within said delay interval in response to a pulse occurring subsequent to said first voltage pulse to prevent operation of said circuit disabling means.

Claim 10

A circuit for restricting use of a telephone comprising: first and second telephone signal conductors; voltage regulator means in said first conductor adapted to provide circuit operating voltage Thereacross; first and second latch circuits, said latch circuits including conductor means, conductor switching means and switching control means, said switching control means being adapted to operate said conductor switching means to control conduction of said conductor means and said conductor means being connected in series across said voltage regulator means; and, a time delayed circuit disabling means including means to effectively short circuit said first telephone signal conductor to second telephone signal conductor and delay means connected to said first latch circuit conductor means adapted to provide a delay interval between operation of said first latch circuit and operation of said short circuiting means, said first latch circuit being adapted to operate in response to an initial pulse in a dial signal to provide a conductive path between second latch circuit and said first conductor and to apply said voltage across said disabling circuit means, said second latch circuit adapted to operate within said delay interval in response to a pulse occurring subsequent to said first voltage pulse to prevent operation of said circuit disabling means.

Claim 11

The circuit of claim 7 wherein said circuit disabling means includes a transistor having emitter and collector terminals connected to said first and second telephone signal conductors respectively, and an R. C. circuit connected to said base and said emitter terminals of said transistor and to said first circuit means, whereby the application of said voltage across said disabling circuit means triggers said transistor into conduction following a delay interval to effectively short circuit said first telephone signal conductor to said second telephone signal conductor.

Claim 12

The circuit of claim 8 wherein each of said first and said second latch circuits includes a silicon controlled rectifier, said silicon controlled rectifiers being separately triggered into conduction by means of dial signal pulses carried by said telephone signal conductors, said silicon controlled rectifiers and said transistor in said circuit disabling means being adapted to cease conduction upon termination of said voltage across said voltage regulator means, whereby the circuit is reset for repeat operation.

Claim 13

The circuit of claim 9 wherein said R. C. circuit is adapted to provide a delay interval greater than the interval between consecutive pulses produced by the dialing of a signal digit on a telephone.

Claim 14

The circuit of claim 7 including means to indicate operation of said circuit disabling means.

Claim 15

A circuit for restricting use of a telephone where the first dialed digit is a designated digit comprising: signal conducting means adapted to carry telephone dial signals each of a different frequency including the dial signal of said first dialed digit; voltage regulator means in said conducting means being adapted to provide a voltage thereacross; a band pass filter; a first latch circuit including control means connected to said signal conducting means through said pass band filter; a band reject filter adapted to block dial signals of the frequencies of said designated digits; a second latch circuit connected to said first latch circuit including control means connected to said signal conducting means through said band reject filter; and, a time delayed circuit disabling means connected to said signal conducting means and to said first latch circuit, said circuit disabling means being adapted to be activated by application thereto of said voltage across said voltage regulating means to prevent transmission of signals by said signal conducting means upon elapse of a delay interval; said first latch circuit being operable in response to the dial signal of said first dialed digit within the pass frequency of said pass band filter to connect said second latch circuit to said signal conducting means and to apply said voltage to said time delayed disabling circuit; said second latch circuit being adapted to operate in response to said first dial signal occurring within said delay interval when outside the frequency range blocked by said band reject filter to prevent operation of said disabling circuit.

Claim 16

A circuit for restricting use of a telephone where the first dialed digit is a designated digit comprising: signal conducting means adapted to carry telephone dial signals each of a different frequency including the dial signal of said first dialed digit; voltage regulator means in said conducting means being adapted to provide a voltage thereacross; a band pass filter; a first latch circuit including control means connected to said signal conducting means through said pass band filter; a band reject filter adapted to block dial signals of the frequencies of said designated digits; a second latch circuit connected to said first latch circuit including control means connected to said signal conducting means through said band reject filter; and, a time delayed circuit disabling means connected to said signal conducting means and to said first latch circuit, said circuit disabling means being adapted to be activated by application thereto of said voltage across said voltage regulating means to prevent transmission of signals by said signal conducting means upon elapse of a delay interval; said first latch circuit being operable in response to the dial signal of said first dialed digit within the pass frequency of said pass band filter to connect said second latch circuit to said signal conducting means and to apply said voltage to said time delayed disabling circuit; said second latch circuit being adapted to operate in response to said first dial signal occurring within said delay interval when outside the frequency range blocked by said band reject filter to prevent operation of said disabling circuit.