Toll-call restriction system

Claim 2

A toll call restriction system for use with telephone lines, comprising: input means for coupling to said lines for successively sensing signals on said lines corresponding to the first m dialed digits of the number of a telephone to be reached and for producing m digit-representing signals; first means coupled to said input means and including m counter means arranged in a sequence from one to m for storing numbers in the first through mth counter means, the numbers corresponding to the first through mth dialed digits as represented by said m signals, said stored m numbers in said counter means forming an m-number combination; read only memory means coupled to said m counter means and responsive to the m-number combination therein for providing a first control signal only when said m -number combination does not correspond to any one in a plurality of m-number combinations defined in said read only memory means, each mnumber combination of said plurality of combinations representing the exchange-identifying portion of a telephone number; a timer coupled to said input means and enabled after said m numbers are stored in said m counter means for providing a second control signal for a preselected first period; output means for disconnecting the dialed phone from said lines only when both said first and second control signals are supplied thereto; and display means coupled to said m counter means for displaying the numbers stored therein.

Claim 3

The system as described in claim 1 wherein the potential across said lines is of a first level when the controlled phone cradle is depressed and is of a second level lower than said first level when the cradle is released, said input means including means for resetting each of said m counter means to an all zero count when the potential across said lines rises from second level to said first level for not less than a required period for the telephone system to re-establish the dial tone condition for said controlled phone, said first period during which said timer provides said second control signal being not less than said required period.

Claim 4

The system as described in claim 2 wherein none of the m-number combinations defined in said read only memory includes a first number corresponding to the digit zero, and the restriction system includes means for sensing the number stored in said first counter means after the first digit is dialed on said controlled phone, and for activating said timer to supply said second control signal when the number stored in said first counter means corresponds to the digit 0 which is dialed for operator assistance, whereby said output means disconnect said phone from said lines for said first period whenever the first dialed digit is 0.

Claim 5

The system as described in claim 2 further including audible signal generating means activated by said second control signal to produce an audible signal and said output means for applying said audible signal to said phone for the time the latter is disconnected from said lines.

Claim 6

A lock arrangement for a Touch-Tone telephone connected to telephone lines on which in response to each digit key activated on said phone, signals at two frequencies appear on said lines, one of the frequencies being above a known frequency, the signAls being generated for a known minimum period, the arrangement comprising: detecting means coupled to said lines for providing an enabling output only when signals at a frequency above said known frequency appear on said lines; means responsive to said enabling output for providing a control signal of a fixed duration only if the enabling output is produced during a preselected portion of said known minimum period; and output means responsive to said control signal for disconnecting said Touch-Tone phone from said lines for the fixed duration of said control signal.

Claim 7

A lock arrangement for a Touch-Tone telephone connected to telephone lines on which in response to each digit key activated on said phone, signals at two frequencies appear on said lines, one of the frequencies being above a known frequency, the signAls being generated for a known minimum period, the arrangement comprising: detecting means coupled to said lines for providing an enabling output only when signals at a frequency above said known frequency appear on said lines; means responsive to said enabling output for providing a control signal of a fixed duration only if the enabling output is produced during a preselected portion of said known minimum period; and output means responsive to said control signal for disconnecting said Touch-Tone phone from said lines for the fixed duration of said control signal.

Claim 8

A toll-call restriction system for restricting connection of a dial-type phone connected to telephone lines to selected exchanges, comprising: an input unit connected to said telephone lines on which a sequence of pulses is produced for each digit dialed on said phone, the number of pulses corresponding to the dialed digit, each pulse varying from a first potential level to a second high potential level and of a substantially fixed pulse period, successive pulses within each sequence being spaced apart by a substantially constant interpulse period, said input unit providing on a first output line a pulse for each pulse on said telephone lines and providing on a second output line a shift pulse during a period, definable as an interdigit period which extends between the end of one puse sequence and a succeeding pulse sequence and for providing on a third output line a reset pulse whenever the potential on said telephone lines returns from said first level to said second level for at least a selected period, definable as a phone disconnect period; a shift register, of n binary stages, n m-l, wherein m and n are integers, m defining the number of the first dialed digits of a selected exchange connected to said input means and responsive to each reset pulse for resetting all of its stages except the first to a low binary state and the first stage to a high binary state, said shift register being further responsive to each shift pulse for resetting a stage thereof which is in a high binary state to the low binary state and for setting a succeeding stage to the high binary state, said shift register including n output lines, each associated with a different stage, each output line being at a high level when its associated stage is at said high binary state and at a low level when its associated stage is at a low binary level; m separate serial input counters each adapted to respond to a sequence of one or more pulses supplied thereto for storing a digit-representing number therein corresponding to the number of pulses in the sequence, each counter being resettable by each reset pulse from said input means for storing a zero therein, said counters being arranged in a sequence from l to m; gate means coupled to said counters, to the n output lines of said register which are associated with the first m register stages and to said input means, for supplying each sequence of pulses of the first m sequences of pulses provided by said input means in response to the first m dialed digits to a different one of said counters, whereby after the first m digits are dialed the m counters store m numbers corresponding to the first m dialed digits, and the last shift register state is at said high binary state; a read only memory coupled to said m counters and responsive to the m-number combination therein for providing a first control signal only when the m-number combination in said counters does not match any combination in a plurality of m-number combinations defined in said read-only memory, the m-number combinations in said memory representing the numerical designations of selected exchanges; a timer coupled to the output line associated with the last register stage for providing a second control signal for a fixed period following the switching of the last register sTage from said low binary level to said high binary level; and output means for disconnecting said phone from the telephone lines when both said first and second control signals are simultaneously applied thereto.

Claim 9

A toll-call restriction system for restricting connection of a dial-type phone connected to telephone lines to selected exchanges, comprising: an input unit connected to said telephone lines on which a sequence of pulses is produced for each digit dialed on said phone, the number of pulses corresponding to the dialed digit, each pulse varying from a first potential level to a second high potential level and of a substantially fixed pulse period, successive pulses within each sequence being spaced apart by a substantially constant interpulse period, said input unit providing on a first output line a pulse for each pulse on said telephone lines and providing on a second output line a shift pulse during a period, definable as an interdigit period which extends between the end of one puse sequence and a succeeding pulse sequence and for providing on a third output line a reset pulse whenever the potential on said telephone lines returns from said first level to said second level for at least a selected period, definable as a phone disconnect period; a shift register, of n binary stages, n m-l, wherein m and n are integers, m defining the number of the first dialed digits of a selected exchange connected to said input means and responsive to each reset pulse for resetting all of its stages except the first to a low binary state and the first stage to a high binary state, said shift register being further responsive to each shift pulse for resetting a stage thereof which is in a high binary state to the low binary state and for setting a succeeding stage to the high binary state, said shift register including n output lines, each associated with a different stage, each output line being at a high level when its associated stage is at said high binary state and at a low level when its associated stage is at a low binary level; m separate serial input counters each adapted to respond to a sequence of one or more pulses supplied thereto for storing a digit-representing number therein corresponding to the number of pulses in the sequence, each counter being resettable by each reset pulse from said input means for storing a zero therein, said counters being arranged in a sequence from l to m; gate means coupled to said counters, to the n output lines of said register which are associated with the first m register stages and to said input means, for supplying each sequence of pulses of the first m sequences of pulses provided by said input means in response to the first m dialed digits to a different one of said counters, whereby after the first m digits are dialed the m counters store m numbers corresponding to the first m dialed digits, and the last shift register state is at said high binary state; a read only memory coupled to said m counters and responsive to the m-number combination therein for providing a first control signal only when the m-number combination in said counters does not match any combination in a plurality of m-number combinations defined in said read-only memory, the m-number combinations in said memory representing the numerical designations of selected exchanges; a timer coupled to the output line associated with the last register stage for providing a second control signal for a fixed period following the switching of the last register sTage from said low binary level to said high binary level; and output means for disconnecting said phone from the telephone lines when both said first and second control signals are simultaneously applied thereto.

Claim 10

The system as described in claim 6 wherein the interdigit period is not less than 250 ms and said input means include means for providing said shift pulse x ms after the end of a last received pulse in a sequence, where x is not greater than 250 ms and is greater than the interpulse period.

Claim 11

The system as described in claim 7 wherein the second control signal duration from said timer is not less that the disconnect period.

Claim 12

The system as described in claim 8 wherein said system further includes means for displaying the numbers stored in said m counters.

Claim 13

The system as described in claim 6 further including abort means coupled to said first counter and to the second output line of said shift register for sensing the number stored in said first counter and for activating said timer after a digit is stored in said first counter and the register''s second stage is shifted to said high binary state only if the number stored in said first counter is a number representing the telephone digit 0, said read only memory being characterized by combinations defined therein none of which includes the number 0 as the first number, whereby when the first dialed digit is 0, thereby indicating telephone operator assistance request, said output means disconnects said dialed phone from the telephone lines for the time of the second control signal from said timer.

Claim 14

The system as described in claim 10 wherein the interpulse period is less than y ms, the interdigit period is not less than z ms with said input means including means for providing a shift pulse whenever the line potential is at said first low lever x ms after a last pulse on said lines, where z > x > y, and said input means further including means for providing said reset pulse whenever the potential of said lines changes from said first level to said second level for not less than x ms, x ms defining the minimum disconnect period.

Claim 15

The system as described in claim 10 further including audio signal generating means for generating an audio signal during the duration of said control signal, and means for connecting said generating means to said output means to apply the audio signal to the dialed phone when the latter is disconnected from said lines.

Claim 16

The system as described in claim 6 further including audio signal generating means for generating an audio signal during the duration of said second control signal, and means for connecting said generating means to said output means to apply the audio signal to the dialed phone when the latter is disconnected from said lines.

Claim 17

The system as described in claim 10 wherein the potential of said lines drops from said first level to a third lower level during the duration of the connection between said controlled phone and another phone, said level change being provided on a fourth output line of said input means, said system including storing means storing the charges for calls from said controlled phone to phones at exchanges represented by the m-number combinations in said memory, and means connected to said input means, said counters and said storing means, for computing the charges of a completed communication as a function of its duration, the n-number combination in the counters and the charge in said storing means.

Claim 18

The system as described in claim 14 further including audio signal generating means for generating an audio signal during the duration of said control signal, and means for connecting said generating means to said output means to apply the audio signal to the dialed phone when the latter is disconnected from said lines.

Claim 19

A toll-call restriction system for restricting the communication betwEen a Touch-Tone phone and any phone reachable through selected exchanges, by controlling the connection of the Touch-Tone phone to the telephone lines as a function of the first m dialed digits, the Touch-Tone phone being of the type whereby as the receiver is raised and the receiver cradle is released, the potential on said lines drops from a first level to a second level, and as each digit is dialed signals at two frequencies, definable as tones, pass through said lines, one of said tones being one of three selected high tones, the system comprising: first means coupled to said lines for detecting the two tones thereon while each digit is dialed and for providing an output in the form of a coded number identifying the dialed digit as a function of the detected tones; m register means each adapted to store each of the coded numbers from said first means, m being an integer and equal to the number of the first dialed digits representing the exchange of the phone whose number is dialed, said m registers being arranged in a sequence; second means responsive to said input means for providing a shift pulse whenever one of the three high tones is detected by said input means for a preselected tone-indicating period; control means responsive to said shift pulse and including gate means connected between said input means and said m registers, for controlling the registers in said register sequence the coded numbers representing the first through mth dialed digits, said control means including means for providing a timer-enabling signal after all the m numbers from said input means are stored in said m registers; a read only memory connected to said m registers and storing a plurality of m-number combinations representing exchanges reachable by said Touch-tone phone for providing a first control signal only when the numbers in said m registers, representing an m-number combination, matches any of the m-number combinations in said read only memory; a timer connected to said control means and responsive to the timer-enabling signal therefrom, for providing a second control signal for a selected period following each received timer-enabling signal; and output means responsive to said first and second control signals for disconnecting said Touch-Tone phone from said lines during the duration that both said control signals are supplied thereto.

Claim 20

A toll-call restriction system for restricting the communication betwEen a Touch-Tone phone and any phone reachable through selected exchanges, by controlling the connection of the Touch-Tone phone to the telephone lines as a function of the first m dialed digits, the Touch-Tone phone being of the type whereby as the receiver is raised and the receiver cradle is released, the potential on said lines drops from a first level to a second level, and as each digit is dialed signals at two frequencies, definable as tones, pass through said lines, one of said tones being one of three selected high tones, the system comprising: first means coupled to said lines for detecting the two tones thereon while each digit is dialed and for providing an output in the form of a coded number identifying the dialed digit as a function of the detected tones; m register means each adapted to store each of the coded numbers from said first means, m being an integer and equal to the number of the first dialed digits representing the exchange of the phone whose number is dialed, said m registers being arranged in a sequence; second means responsive to said input means for providing a shift pulse whenever one of the three high tones is detected by said input means for a preselected tone-indicating period; control means responsive to said shift pulse and including gate means connected between said input means and said m registers, for controlling the registers in said register sequence the coded numbers representing the first through mth dialed digits, said control means including means for providing a timer-enabling signal after all the m numbers from said input means are stored in said m registers; a read only memory connected to said m registers and storing a plurality of m-number combinations representing exchanges reachable by said Touch-tone phone for providing a first control signal only when the numbers in said m registers, representing an m-number combination, matches any of the m-number combinations in said read only memory; a timer connected to said control means and responsive to the timer-enabling signal therefrom, for providing a second control signal for a selected period following each received timer-enabling signal; and output means responsive to said first and second control signals for disconnecting said Touch-Tone phone from said lines during the duration that both said control signals are supplied thereto.

Claim 21

The system as described in claim 16 further including means coupled to said m register means for displaying m numbers corresponding to the coded number in said m counter means.

Claim 22

The system as described in claim 16 further including audio signal generating means coupled to said timer for providing an audio signal during the second control signal period, and means for connecting said generating means to said output means to apply the generated audio signal to said Touch-Tone phone when the latter is disconnected from said lines.

Claim 23

The system as described in claim 16 wherein none of the m-number combinations in said memory includes a first number corresponding to the dialed digit 0, which is dialed first for operator assistance, said system further including operator call abort means for sensing the coded number stored in said first register after the first digit is dialed on said Touch-Tone phone and for activating said timer to provide said second control signal when the coded number in said first register corresponds to the dialed digit 0.