US3757055A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic toll restrictor
Assignee: Individual
•
Filing: 1972-03-21
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Granted: 1973-09-04
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Expires: 1992-03-21
Abstract
Abstract An apparatus for preventing unauthorized long distance calls from a conventional dial or push-button telephone including a switch connecting the telephone to the telephone lines, a counting circuit which counts the number of digits dialed and causes the switch to be opened when the count reaches eight, and a logic circuit which also causes the switch to be opened whenever the digit zero is among the first three digits dialed. The apparatus can be disposed either at the users facility or at a central telephone exchange.
Inventors
- 👤 Cann G Mc
- 👤 J Landis
- 👤 J Kimbrell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:38
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/66; H04M1/677; H04Q; H04Q3/00; H04Q3/58; H04Q3/62; H04Q3/625
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
340 words
Apparatus for preventing unauthorized long distance telephone calls through telephone lines to a central telephone facility from a telephone having digit generating means for producing a plurality of digit signals each associated with one digit, said plurality of digits defining a telephone number including: switch means having A first position connecting said telephone to said telephone lines for permitting transmission of telephone signals and a second position disconnecting said telephone from said telephone lines for preventing transmission of telephone signals, means connected to said digit generating means for receiving said digit signals, counting the number of digits produced and storing the current count, first logic means connected to said receiving, counting and storing means for shifting from a first to second condition following when said receiving, counting and storing means stores a count of three, and no later than when said receiving, counting and storing means stores a count of four, second logic means connected to said first logic means and to said digit generating means for producing a given output signal when said first logic means is in said first condition and said digit producing means produces a digit signal associated with the digit zero, third logic means connected to said second logic means and to said receiving, counting and storing means for producing a disabling signal whenever said second logic means produces said given output signal or said receiving, counting and storing means stores a count of eight indicating that eight digit signals have been produced by said digit generating means, switch controlling means connected to said third logic means for receiving said disabling signal and causing said switch means to shift from said first to said second position whenever said disabling signal is received, and means connected to said receiving, counting and storing means, and said first logic means for causing the count stored in said receiving, counting and storing means to be reset to zero, and said first logic means to be shifted from said second to said first condition after said disabling signal is produced.
Claim 2
Dependent Claim
340 words
Apparatus for preventing unauthorized long distance telephone calls through telephone lines to a central telephone facility from a telephone having digit generating means for producing a plurality of digit signals each associated with one digit, said plurality of digits defining a telephone number including: switch means having A first position connecting said telephone to said telephone lines for permitting transmission of telephone signals and a second position disconnecting said telephone from said telephone lines for preventing transmission of telephone signals, means connected to said digit generating means for receiving said digit signals, counting the number of digits produced and storing the current count, first logic means connected to said receiving, counting and storing means for shifting from a first to second condition following when said receiving, counting and storing means stores a count of three, and no later than when said receiving, counting and storing means stores a count of four, second logic means connected to said first logic means and to said digit generating means for producing a given output signal when said first logic means is in said first condition and said digit producing means produces a digit signal associated with the digit zero, third logic means connected to said second logic means and to said receiving, counting and storing means for producing a disabling signal whenever said second logic means produces said given output signal or said receiving, counting and storing means stores a count of eight indicating that eight digit signals have been produced by said digit generating means, switch controlling means connected to said third logic means for receiving said disabling signal and causing said switch means to shift from said first to said second position whenever said disabling signal is received, and means connected to said receiving, counting and storing means, and said first logic means for causing the count stored in said receiving, counting and storing means to be reset to zero, and said first logic means to be shifted from said second to said first condition after said disabling signal is produced.
Claim 3
Dependent Claim
120 words
Apparatus as in claim 1 further including means connected to said digit signal producing means for generating at least a single electrical pulse for each digit signal produced and wherein said receiving, counting and storing means includes a monostable multivibrator connected to said pulse generating means for producing, upon receipt of the first pulse from said digit generating means, a pulse having a duration greater than the duration from the first to the last of all of the pulses generated for any given digit signal, and a plurality of flip-flops connected to said monostable multivibrator and to each other to accumulate a count and increase that count by one when said longer duration pulse is produced by said monostable multivibrator.
Claim 4
Dependent Claim
70 words
Apparatus as in claim 2 wherein said first logic means includes a given flip-flop having an input connected to said flip-flops of said receiving, counting and storing means and having an output establishing a first output condition when the count in said receiving, counting and storing means is three or greater and a second output condition when the count in said receiving, counting and storing means is less than three.
Claim 5
Dependent Claim
86 words
Apparatus as in claim 3 wherein said causing means includes a further monostable multivibrator connected to said monostable multivibrator in said receiving, counting and storing means for producing a further pulse upon the termination of the pulse produced by said multivibrator of said receiving, counting and storing means and means connecting said further multivibrator to said flip-flop of said second logic means for transmitting said further pulse to cause that flip-flop to shift from its second to first output condition upon receipt of said further pulse.
Claim 6
Dependent Claim
100 words
Apparatus as in claim 4 wherein said third logic means includes a monostable multivibrator having inputs connected to the flip-flops of said receiving, counting and storing means and to said second logic means for producing a given pulse whenever said second logic means produces said given output signal or said receiving, counting and storing means stores a count of eight and wherein said causing means includes a relay connected to said multivibrator of said third logic means for causing said switch means to open while said relay is receiving said given pulse from said multivibrator of said third logic means.
Claim 7
Dependent Claim
151 words
Apparatus as in claim 5 wherein said digit signal generating means generates a pulse train comprising each digit signal with the number of pulses identifying the digit and ten pulses being associated with the digit zero and wherein said second logic means includes a plurality of flip-flops interconnected for counting and for providing a predetermined output signal when the count therein reaches ten, a logic gate having its output connected to said plurality of flip-flops of said second logic means, one input connected to said digit signal generating means and other input connected to said given flip-flop of said second logic means for passing said pulses from said digit signal generating means to said plurality of flip-flops of said second logic means when said given flip-flop is in said first condition and not passing said pulses from said digit signal generating means when said given flip-flop is in said second condition.
Claim 8
Dependent Claim
128 words
Apparatus as in claim 5 wherein said digit signal generating means generates a signal having unique frequency component identifying each digit and wherein said second logic means includes means connected to said digit signal generating means for producing a predetermined output signal when the signal associated with the digit zero is produced, a logic gate having one input connected to the output of said predetermined signal producing means and another input connected to the output connected to said given flip-flop of said second logic means and having its output connected to said monostable multivibrator of said third logic means for passing a signal to said monostable multivibrator of said third logic means for causing that multivibrator to produce said given pulse when said logic gate passes said signal.
Claim 9
Dependent Claim
17 words
Apparatus as in claim 7 further wherein said predetermined signal producing means includes an audio frequency filter.
Claim 10
Dependent Claim
9 words
Apparatus as in claim 1 further including said telephone.
Claim 11
Dependent Claim
30 words
Apparatus as in claim 1 further including manually operable switch means connected to said lines and having a first position enabling said apparatus and a second position disabling said apparatus.
Claim 12
Dependent Claim
32 words
Apparatus as in claim 10 wherein said apparatus is disposed at the central telephone facility and further including means at said facility for detecting the position of said manually operable switch means.
Claim 13
Dependent Claim
27 words
Apparatus as in claim 11 wherein said manually operated switch unbalances said lines in said first position and said detecting means includes means for detecting said unbalance.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |