Telephone call restrictor

Claim 2

A telephone call restrictor comprising: a digit register means for receiving a plurality of digits of a multi-digit telephone number from a telephone line; means for coupling said digit register means to said telephone line; decoding means coupled to said digit register means and responsive to a first predetermined number of said plurality of digits for providing a first plurality of outputs; second means coupled to said digit register means and addressable by a second predetermined number of said plurality of digits for providing a second plurality of outputs; and means responsive to said first and said second pluralities of outputs for providing an interrupt signal to prevent the completion of a call to said telephone number in the absence of a predetermined correspondence between said first and said second outputs.

Claim 3

A telephone call restrictor according to claim 1 wherein one of said plurality of digits is a predetermined digit, and further comprising means coupled to said digit register means and responsive to said predetermined digit for providing an interrupt signal to prevent the completion of a telephone call using said one digit.

Claim 4

A telephone call restrictor according to claim 1 wherein said first means for providing a first output in response to a first one of said plurality of digits comprises decoding means having a plurality of output lines for providing said first output on a predetermined one of said plurality of output lines, said predetermined one of said plurality of output lines being determined by the numerical value of said first digit and wherein said second means for providing a second output in response to the others of said plurality of digits comprises an addressable memory means addressable by said others of said plurality of digits having a plurality of output lines for providing said second output.

Claim 5

A telephone call restrictor according to claim 3 wherein said addressable memory means comprises means for storing predetermined codes for comparison with said first output from said decoding means.

Claim 6

A telephone call restrictor according to claim 1 wherein said digit register means comprises a plurality of digit registers and said coupling means comprises means for routing each of said plurality of digits to a predetermined one of said digit registers.

Claim 7

A telephone call restrictor according to claim 5 wherein said routing means comprises: a digit detector for detecting each digit in said plurality of digits; a counter coupled to said digit detector having a plurality of stages for counting said detected digits and gate means responsive to said counting of said digits having an input for receiving said digits and being coupled between said counter stages and said plurality of digit registers for providing said routing of said digits to said digit registers.

Claim 8

A telephone call restrictor according to claim 1 wherein said plurality of digits are represented by multi-frequency a.c. signals and said coupling means comprises means for converting said a.c. signals to a predetermined number of voltage pulses, said predetermined number of voltage pulses being determined by the numerical value of each of said digits.

Claim 9

A telephone call restrictor according to claim 1 wherein said digit register means comprises a plurality of digit registers each having a plurality of corresponding output lines, said first means comprising a decoding means having a plurality of output lines, and said second means comprising a plurality of addressable memory means, each having a plurality of corresponding address lines and a plurality of corresponding output lines and further comprising: means for coupling corresponding ones of said output lines of each of said digit registers to said address lines of a corresponding one of each of said memory means; a first plurality of gate means each having a plurality of input lines and an output line; means for coupling corresponding ones of said output lines of each of said memories to said input lines of a corresponding one of each of said first plurality of gate means; a second plurality of gate means each having a plurality of input lines and an output line; and means for coupling a corresponding one of each of said second plurality of gate means to said output line of a corresponding one of said first plurality of gate means and a corresponding output line of said decoding means for providing said interrupt signal on at least one of said output lines of said second plurality of gate means in the event there is said unacceptable correspondence between said first and said second outputs.

Claim 10

A telephone call restrictor comprising: digit register means for receiving the storing a plurality of digits of a multi-digit telephone number; decoding means for decoding a first one of said plurality of digits stored in said digit register means for providing a predetermined output corresponding to the numerical value of said first digit; memory means having a plurality of memory locations addressable by said remaining ones of said plurality of digits in said digit register means, in which predetermined ones of said locations contain a code corresponding to an acceptable combination of said plurality of digits and operable in response to said remaining ones of said plurality of digits for providing an output from said memory locations; and means responsive to an output from said decoding means and an output from said memory means for comparing said outputs and providing an interrupt signal in the absence of a predetermined correspondence between said outputs.

Claim 11

A telephone call restrictor comprising: digit register means for receiving the storing a plurality of digits of a multi-digit telephone number; decoding means for decoding a first one of said plurality of digits stored in said digit register means for providing a predetermined output corresponding to the numerical value of said first digit; memory means having a plurality of memory locations addressable by said remaining ones of said plurality of digits in said digit register means, in which predetermined ones of said locations contain a code corresponding to an acceptable combination of said plurality of digits and operable in response to said remaining ones of said plurality of digits for providing an output from said memory locations; and means responsive to an output from said decoding means and an output from said memory means for comparing said outputs and providing an interrupt signal in the absence of a predetermined correspondence between said outputs.

Claim 12

A telephone call restrictor for allowing calls to acceptable telephone numbers and preventing calls to unacceptable telephone numbers comprising: first register means for storing a first digit of a plurality of digits of a multi-digit telephone number; second register means for storing the remaining ones of said plurality of digits of said multi-digit telephone number; decoding means having a first plurality of output lines coupled to said first register means and responsive to said first digit for decoding said first digit and outputing a predetermined signal on one of said first plurality of output lines; memory means having a second plurality of output lines corresponding to said first plurality of output lines coupled to said second register means and responsive to predetermined ones of said remaining ones of said plurality of digits for outputing a predetermined signal on one of said second plurality of output lines; means matching the output signals on corresponding pairs of said first and second plurality of output lines for providing an interrupt signal if there is no match between the output signals on any of said pairs; and means responsive to said interrupt signal for preventing the completion of a telephone call to said telephone number causing said interrupt signal.

Claim 13

A telephone call restrictor for allowing calls to acceptable telephone numbers and preventing calls to unacceptable telephone numbers comprising: first register means for storing a first digit of a plurality of digits of a multi-digit telephone number; second register means for storing the remaining ones of said plurality of digits of said multi-digit telephone number; decoding means having a first plurality of output lines coupled to said first register means and responsive to said first digit for decoding said first digit and outputing a predetermined signal on one of said first plurality of output lines; memory means having a second plurality of output lines corresponding to said first plurality of output lines coupled to said second register means and responsive to predetermined ones of said remaining ones of said plurality of digits for outputing a predetermined signal on one of said second plurality of output lines; means matching the output signals on corresponding pairs of said first and second plurality of output lines for providing an interrupt signal if there is no match between the output signals on any of said pairs; and means responsive to said interrupt signal for preventing the completion of a telephone call to said telephone number causing said interrupt signal.

Claim 14

A telephone call restrictor according to claim 1 wherein said coupling means comprises: a plurality of ON/OFF hook detector circuit means; means for coupling each of said detector circuit means to a predetermined one of a plurality of telephone lines; means for coupling each of said detector circuit means to a multi-line bus circuit means; means for coupling said digit register means to said bus circuit means; and means for interrogating each of said detector circuit means and responsive to a first output signal from a first one of said detector circuit means for providing a first transfer of digits of a telephone number to said digit register means via said bus circuit means from said telephone line to which said first one of said detector circuits is coupled, and for preventing the transfer of digits of a telephone number to said digit register means from another of said telephone lines until said first transfer is completed.

Claim 15

A telephone call restrictor according to claim 11 wherein said detector circuit means interrogating means comprises: means for interrogating each of said plurality of detector circuit means in a predetermined sequence for a predetermined input signal.

Claim 16

A telephone call restrictor according to claim 12 wherein said interrogating means comprises: a plurality of gate means; a counter coupled to said gate means; and means for coupling said counter to a source of clock pulses for advancing said counter and enabling said gate means in a predetermined sequence, said gate means, if enabled, being responsive to said predetermined input signal from said first one of said plurality of detector circuit means for inhibiting the advancement of said counter, and responsive to a termination of said predetermined input signal upon the completion of said first transfer of digits for enabling the further advancement of said counter.

Claim 17

A telephone call restrictor according to claim 13 wherein each of said plurality of detector circuits comprises reset circuit means responsive to a change in potential occurring on a telephone line to which it is connected for providing said predetermined input signal to said gate means.

Claim 18

A telephone call restrictor according to claim 14 wherein said reset circuit means comprises means responsive to a change in potential occurring on a telephone line to which it is connected when the cradle switch of a telephone unit coupled to said line is switched.

Claim 19

A telephone call restrictor according to claim 15 wherein each of said plurality of detector circuits comprises: switch means; means for coupling said switch means to the telephone line to which an associated detector circuit is coupled; and switch control means responsive to an input signal coupled to said switch means for controlling the opening and closing of said switch means, said opening of said switch means serving to prevent the transmission of electrical signals on said telephone line, and said closing of said switch means serving to cause a dial tone on said telephone line.

Claim 20

A telephone call restrictor according to claim 16 wherein each of said plurality of detector circuits comprises: first means responsive to a first input from said reset circuit means for opening said switch means and to a second input from said detector circuit interrogating means for closing said switch means; and second means responsive to said interrupt signal providing means for opening said switch means for a predetermined period of time.

Claim 21

A telephone call restrictor according to claim 17 wherein said predetermined period of time is of sufficient length to insure the appearance of a dial tone on the telephone line upon said closing of said switch means.

Claim 22

A telephone call restrictor apparatus operable in response to digits of a telephone number dialed on a telephone line comprising: decoding means responsive to a first predetermined number of said digits for decoding said first predetermined number of digits and providing a first output; means responsive to a second predetermined number of said digits for decoding said second predetermined number of said digits and providing a second output; and means responsive to said first and said second outputs for preventing the completion of a call to said telephone number in the absence of a predetermined correspondence between said first and said second outputs.

Claim 23

A telephone call restrictor apparatus operable in response to digits of a telephone number dialed on a telephone line comprising: decoding means responsive to a first predetermined number of said digits for decoding said first predetermined number of digits and providing a first output; means responsive to a second predetermined number of said digits for decoding said second predetermined number of said digits and providing a second output; and means responsive to said first and said second outputs for preventing the completion of a call to said telephone number in the absence of a predetermined correspondence between said first and said second outputs.

Claim 24

An apparatus according to claim 19 wherein said preventing means comprises means for providing a dial tone on said telephone line.

Claim 25

An apparatus according to claim 19 wherein said first output providing means comprises: first decoding means having a plurality of outputs for decoding said first predetermined number of digits; said second output providing means comprises second decoding means having a plurality of outputs for decoding said second predetermined number of digits; and said preventing means comprises comparing means for comparing said outputs of said first and said second decoding means.

Claim 26

An apparatus according to claim 21 wherein said first decoding means comprises a 1-out-of-N decoding means, said second decoding means comprises an addressable memory means addressable by said second predetermined number of digits and said preventing means comprises means responsive to said 1-out-of-N decoding means and said addressable memory means for providing a dial tone on said telephone line.