Patent US3784757A successfully refreshed from Google Patents.
US3784757A
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US
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Limited access dialing system
Assignee: INFORMATION FLOW Inc
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Filing: 1971-06-14
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Granted: 1974-01-08
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Expires: 1991-06-14
Abstract
Abstract A limited access dialing system having a plurality of line monitors each connected in parallel to a separate trunk line to be monitored and communicating through parallel lines to a central memory system containing a list of authorized telephone numbers. The line monitor unit counts the pulses of each digit and stores the digits in a number register. It determines if an area code has been dialed and if a leading ''''1'''' has been dialed and accommodates for them. The central memory system sequentially interrogates the line monitors until it finds one which is storing a number in its registers. It then stops interrogating and checks the number stored against the authorized list. If the number is authorized the line monitor is reset and the sequential interrogating is resumed. If the number is not authorized, the trunk line is interrupted before resetting. The numbers in the list can be updated by entering or removing numbers through a control panel.
Inventors
- 👤 J Woolf
- 👤 R Sadowy
- 👤 R Gershman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:58
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/38
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
167 words
In a telephone system including a plurality of telephone sets each able to be coupled to a trunk line, a limited access switching system comprising a central memory system and a plurality of line monitor units, each line monitor unit including: switching means in series with a trunk line; monitor means connected in parallel with said trunk line, and detection means capable of detecting through said monitor means a number dialed onto said trunk line, and wherein said central memory system comprises: memory means containing a list of authorized telephone numbers; comparison means for comparing the number dialed with the number in said authorized list, and menas for said central memory system sequentially interrogating each of said line monitor units including a plurality of selection means each one of which is associated with one of said line monitor units, said selection means being serially connected such that the output of the selection means of one unit enables the input of the selection means of the next unit.
Claim 2
Dependent Claim
167 words
In a telephone system including a plurality of telephone sets each able to be coupled to a trunk line, a limited access switching system comprising a central memory system and a plurality of line monitor units, each line monitor unit including: switching means in series with a trunk line; monitor means connected in parallel with said trunk line, and detection means capable of detecting through said monitor means a number dialed onto said trunk line, and wherein said central memory system comprises: memory means containing a list of authorized telephone numbers; comparison means for comparing the number dialed with the number in said authorized list, and menas for said central memory system sequentially interrogating each of said line monitor units including a plurality of selection means each one of which is associated with one of said line monitor units, said selection means being serially connected such that the output of the selection means of one unit enables the input of the selection means of the next unit.
Claim 3
Dependent Claim
43 words
The switching system as in claim 1 and further including parallel bus lines interfacing between said line monitor units, all of which are connected in parallel to said bus lines and said central memory system which is connected directly to said bus lines.
Claim 4
Dependent Claim
42 words
The switching system as in claim 1, wherein said switching means further include switches serially interconnected within said trunk line, a relay coil controlling said switches and relay control means for energizing said relay coil and controlled by said central memory system.
Claim 5
Dependent Claim
103 words
The switching system as in claim 1, wherein said detection means further incLude, pulse counting means for counting the pulses as dialed onto said trunk line, digit detector means for sensing the end of a dialed digit and producing an end of digit signal, digit counting means for counting the number of digits dialed, register means for storing the telephone number dialed, and control means controlled by said end of digit signal and in response thereto storing the pulses counted by said pulse counting means into said register means, resetting said pulse counting means and advancing the count on said digit counting means.
Claim 6
Dependent Claim
31 words
The switching system as in claim 4, wherein said detection means further include, number detector means for sensing the end of a dialed number and producing an end of number signal.
Claim 7
Dependent Claim
52 words
The switching system as in claim 5, wherein said detection means further include area code detection means capable of detecting the presence of a dialed area code and in response thereto setting said number detector means for sensing ten dialed digits and wherein said number detector means normally senses seven dialed digits.
Claim 8
Dependent Claim
29 words
The switching system as in claim 6, wherein said area code detection means include means to detect the presence of a 1 or 0 in the second dialed digit.
Claim 9
Dependent Claim
44 words
The switching system as in claim 5, wherein said detection means further include leading 1 detection means capable of detecting the presence of a dialed leading 1 and in response thereto inhibiting said control means from advancing the count on said digit counting means.
Claim 10
Dependent Claim
35 words
The switching system as in claim 4, and further including open line detecting means for resetting said pulse counting means, said register means and said digit counting means on the occurrence of an open line.
Claim 11
Dependent Claim
36 words
The switching system as in claim 1, wherein each said line monitor unit further includes unrestricted line detector means capable of inhibiting said detection means when the telephone handset is one of a predetermined unrestricted class.
Claim 12
Dependent Claim
42 words
The switching system as in claim 10 including tone generating means connected to the unrestricted telephones for generating a tone on all unrestricted system lines, and wherein said unrestricted line detector means include tone filter means, rectifier means, and level detection means.
Claim 13
Dependent Claim
15 words
The switching system as in claim 1, wherein said monitor means include line isolator means.
Claim 14
Dependent Claim
17 words
The switching system as in claim 12, wherein said line isolator is a high impedance input amplifier.
Claim 15
Dependent Claim
68 words
The switching system as in claim 1, wherein said detection means include means for producing a service request signal upon detecting a number dialed and wherein said means for sequentially interrogating include means to inhibit further interrogation upon receiving a service request signal in response to the interrogation of the line monitor unit producing the request signal and resuming interrogation after said line monitor unit has been serviced.
Claim 16
Dependent Claim
17 words
The switching system as in claim 1, wherein said selection means is a one bit shift register.
Claim 17
Dependent Claim
35 words
The switching system as in claim 1, wherein said means for sequentially interrogating further includes shifting means for causing the outputs of the selection means to sequentially shift from one selection means to the next.
Claim 18
Dependent Claim
43 words
The switching system as in claim 16, wherein said detection means produce an end of number signal and further including means for producing a flag signal at the simultaneous occurrence of the enabling of the selection means and the end of number signal.
Claim 19
Dependent Claim
48 words
The switching system as in claim 17, wherein said comparison means include control means for detecting said flag signal and in response thereto inhibiting said sequentially interrogating means, and comparing the number detected in the line monitor unit which has produced said flag signal with said authorized list.
Claim 20
Dependent Claim
39 words
The switching system as in claim 2, wherein said sequentially interrogating means produce a series of shift signals and wherein said bUs lines include a selector shift bus line which transfers said signals sequentially to successive line monitor units.
Claim 21
Dependent Claim
75 words
The switching system as in claim 19, wherein said detection means produce flag signals after detecting a number dialed and wherein said bus lines further include a data bus and a memory check flag bus, whereby said memory check flag bus transfers said flag signals and said data bus transfers the number detected from the line monitor unit to the memory system, both transfers being subsequent to the line monitor unit receiving a shift signal.
Claim 22
Dependent Claim
100 words
The switching system as in claim 20, wherein said comparison means include clock means for producing a series of clock pulses and reset means for producing a reset signal, said bus lines further including a data control bus and a flag reset bus, whereby said clock pulses are transferred from said memory system to the line monitor unit by said data control bus, after said memory system receives said flag signals, and said reset signal is transferred from said memory system to the line monitor unit by said flag reset bus line after said comparison means has completed the comparison.
Claim 23
Dependent Claim
54 words
The switching system as in claim 21, wherein said comparison means include means for producing an interrupt signal in the absence of a valid comparison, and said bus lines further including a line interrupt bus, whereby said interrupt signal is transferred from said memory system to the switching means in the line monitor unit.
Claim 24
Dependent Claim
63 words
The switching system as in claim 1, wherein said comparison means include first storage means for storing the number detected by said detection means, second storage means for sequentially storing the numbers from said list contained in said memory means, and comparator detection means for comparing the numbers in said first and second storage means and producing an output upon a valid comparison.
Claim 25
Dependent Claim
33 words
The switching system as in claim 23, wherein said comparison means further include sequencing control means for sequentially reading the contents of said list from said memory means to said second storage means.
Claim 26
Dependent Claim
42 words
The switching system as in claim 24, wherein said telephone numbers contain area code digits, exchange digits and line number digits, and wherein said comparator detection means includes means for producing an output at the valid comparison of each type of digits.
Claim 27
Dependent Claim
29 words
The switching system as in claim 25, wherein some of said digits are ''''no care'''' digits and said comparator detection means includes means for recognizing said ''''no care'''' digits.
Claim 28
Dependent Claim
50 words
The switching system as in claim 1, wherein said line monitor unit generates a service request signal upon detecting a dialed number, and wherein said memory system further includes system control means for inhibiting said means for sequentially interrogating upon receiving said service request signal and initiating said comparison means.
Claim 29
Dependent Claim
40 words
The switching system as in claim 27, wherein said system control means include program storage means for registering the change from interrogation to comparison, and instruction generating means for generating a sequence of control signals to control said comparison means.
Claim 30
Dependent Claim
83 words
The switching system as in claim 28, wherein said comparison means include sequencing means for sequentially controlling the comparisons in stepwise sequence through said list and producing an end of memory signal upon reaching the end of said list, comparator means for generating a comparison signal upon detecting a valid comparison and wherein said control means produce a reset signal in response to said comparison signal and an interrupt signal followed by a reset signal in response to said end of memory signal.
Claim 31
Dependent Claim
27 words
The switching system as in claim 29, wherein said comparison means further includes means for recognizing if a particular number in said list has ever been dialed.
Claim 32
Dependent Claim
33 words
The switching system as in claim 30, wherein said recognizing means include a parity bit associated with each numBer in said list which is set upon detecting a valid comparison with such number.
Claim 33
Dependent Claim
51 words
The switching system as in claim 29, wherein said control means further include transition means which in response to the generated control signal, the end of memory signal, the comparison signal and said program storage means, cause said instruction generating means to generate the next of the sequence of control signals.
Claim 34
Dependent Claim
20 words
The switching system as in claim 1, and further including panel control means for controlling operations on said memory system.
Claim 35
Dependent Claim
50 words
The switching system as in claim 33, wherein said panel control means include means for entering new numbers in available positions in said list, means for deleting numbers from said list, means for printing out said list and means for recognizing numbers on said list which have never been dialed.
Claim 36
Dependent Claim
80 words
The switching system as in claim 32 and further including panel control means connected to said program storage means, said panel control means capable of instructing the entering of a new number into said list, the deleting of a number from said list, and the printing out of said list, and wherein said program storage means stores said instructions and in response thereto said transition means causes said instruction generating means to generate control signals to carry out said instructions.
Claim 37
Dependent Claim
22 words
The switching system as in claim 35, wherein said comparison means further include means for recognizing a particular number previously printed out.
Claim 38
Dependent Claim
61 words
The switching system as in claim 1, wherein said detection means further include delay means, responsive to the seventh digit dialed for providing a predetermined delay following said seventh dialed digit, and sensing means for detecting the presence of an eighth dialed digit during said predetermined delay and in response thereto setting said number detector means for sensing 10 dialed digits.
Claim 39
Dependent Claim
37 words
The switching system as in claim 4, wherein said detection means further include zero detection means for detecting the presence of a dialed zero as the first digit and in response thereto triggering said relay control means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-07 | 1977-07-09 | 1978-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-07 | 1981-07-09 | 1982-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-07 | 1985-07-09 | 1986-01-08 | $7700.00 | Window Closed / Lapsed |