US3961140A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Line switch controller for a time-division switching system
Assignee: AT&T Inc
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Filing: 1975-03-21
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Granted: 1976-06-01
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Expires: 1995-03-21
Abstract
Abstract A line switch controller for time division telephone switching systems incorporates the function of a time slot assignment memory. Time slots are defined by the repetitive numerical sequence produced by a local time slot counter in enumerating clock pulses. Line switch closures effecting the connection of parties via a time division bus are performed in response to the attainment of a predetermined count in presettable control counters each dedicated to a different line switch and enumerating clock pulses up to the same maximum enumeration of the time slot counter. Repetitive closure of a line switch in a particular time slot is achieved by setting the corresponding control counter to the predetermined count in that time slot. Quick access to time slot assignment information is attained through the inclusion of a binary multibit subtractor to take the difference between the time slot counter enumeration and the enumeration of a selected control counter. This difference corresponds to the time slot assignment of the party connected to the line switch which the selected control counter controls.
Inventors
- 👤 Robert Lawrence Carbrey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:12
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04J; H04J3/00; H04J3/02; H04J3/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
159 words
In a time division switching system capable of accommodating a plurality of calls, each among a different plurality of parties, said system including a time division bus, a plurality of line switches each operative, upon closure, to connect a different one of said parties to said time division bus and means for repetitively producing a signal having a sequence of distinct values defining a sequence of time slots during each of which a different one of said calls is accommodated, the improvement comprising: a plurality of means, each dedicated to one of said line switches, for generating a control signal having a selectable phase of said producing means signal, a predetermined value of said control signal being effective to close the corresponding line switch, and means for subtracting from said producing means signal the control signal corresponding to the line switch of a particular party, the resulting difference corresponding to the time slot during which said party is accommodated.
Claim 2
Dependent Claim
159 words
In a time division switching system capable of accommodating a plurality of calls, each among a different plurality of parties, said system including a time division bus, a plurality of line switches each operative, upon closure, to connect a different one of said parties to said time division bus and means for repetitively producing a signal having a sequence of distinct values defining a sequence of time slots during each of which a different one of said calls is accommodated, the improvement comprising: a plurality of means, each dedicated to one of said line switches, for generating a control signal having a selectable phase of said producing means signal, a predetermined value of said control signal being effective to close the corresponding line switch, and means for subtracting from said producing means signal the control signal corresponding to the line switch of a particular party, the resulting difference corresponding to the time slot during which said party is accommodated.
Claim 3
Dependent Claim
54 words
The improvement of claim 1 further comprising: means for selecting the control signal which is to be subtracted from said producing means signal, and a plurality of activating means each responsive to the attainment of the predetermined value in a different one of said generating means to enable closure of the corresponding line switch.
Claim 4
Dependent Claim
173 words
In a time division switching system capable of accmmodating a plurality of calls, each among a different plurality of parties, said systems including a time division bus, a plurality of line switches each operative, upon closure, to connect a different one of said parties to said time division bus, a source of clock pulses and a time slot counter, responsive to clock pulses and operative to enumerate clock pulses up to a maximum enumeration which is one less than the number of time slots; the combination of: a plurality of resettable counters each enumerating clock pulses up to a maximum enumeration coextensive with the maximum enumeration of said time slot counter, a plurality of pulsing means each producing a control pulse in response to the attainment of a predetermined enumeration by a different one of said resettable counters, the control pulses from each pulsing means effecting closure of a different one of said line switches, and means for subtracting from said time slot counter enumeration a selected one of said resettable counter enumerations.
Claim 5
Dependent Claim
173 words
In a time division switching system capable of accmmodating a plurality of calls, each among a different plurality of parties, said systems including a time division bus, a plurality of line switches each operative, upon closure, to connect a different one of said parties to said time division bus, a source of clock pulses and a time slot counter, responsive to clock pulses and operative to enumerate clock pulses up to a maximum enumeration which is one less than the number of time slots; the combination of: a plurality of resettable counters each enumerating clock pulses up to a maximum enumeration coextensive with the maximum enumeration of said time slot counter, a plurality of pulsing means each producing a control pulse in response to the attainment of a predetermined enumeration by a different one of said resettable counters, the control pulses from each pulsing means effecting closure of a different one of said line switches, and means for subtracting from said time slot counter enumeration a selected one of said resettable counter enumerations.
Claim 6
Dependent Claim
17 words
The combination of claim 3 further comprising means for resetting a selectable one of said resettable counters.
Claim 7
Dependent Claim
29 words
The combination of claim 3 in which each of said counters further comprises means for presetting said counter enumeration to the instantaneous value of said time slot counter enumeration.
Claim 8
Dependent Claim
87 words
The combination of claim 3 in which said subtracting means employs two's complement arithmetic and comprises: a binary full adder having first and second multibit binary inputs, a least significant carry bit input and a multibit sum output, means for coupling said time slot counter enumeration to said first multibit input, a plurality of inverters each coupling a different bit of said selected resettable counter enumeration to said second multibit input, and means for coupling a constant "logical one" level to said least significant carry bit input.
Claim 9
Dependent Claim
175 words
In a time division telephone switching system including a plurality of line switches selectively actuable for coupling a corresponding plurality of subscriber stations to a time division bus during assigned time slots, said system including a source of clock pulses and means for producing a time slot count sequence defining said time slots, a controller for said line switches comprising: a plurality of control signal generators comprising: a resettable counter for counting clock pulses, means, selectively actuable, for resetting said counter, means, selectively actuable, for reading out the content of said counter, and means responsive to the reinitialization of said counter from its full count for producing a pulse to one of said line switches, thereby activating said line switch, means for subtracting from said time slot count sequence the output of one of said reading means, means for applying outputs of said reading means in parallel to an input of said subtracting means, and means for selecting said reading and resetting means of one of said generators in a time slot of said system.
Claim 10
Dependent Claim
175 words
In a time division telephone switching system including a plurality of line switches selectively actuable for coupling a corresponding plurality of subscriber stations to a time division bus during assigned time slots, said system including a source of clock pulses and means for producing a time slot count sequence defining said time slots, a controller for said line switches comprising: a plurality of control signal generators comprising: a resettable counter for counting clock pulses, means, selectively actuable, for resetting said counter, means, selectively actuable, for reading out the content of said counter, and means responsive to the reinitialization of said counter from its full count for producing a pulse to one of said line switches, thereby activating said line switch, means for subtracting from said time slot count sequence the output of one of said reading means, means for applying outputs of said reading means in parallel to an input of said subtracting means, and means for selecting said reading and resetting means of one of said generators in a time slot of said system.
Claim 11
Dependent Claim
33 words
The controller of claim 7 in which the counter in each of said control signal generators further comprises means for presetting said counter to the instantaneous value of said time slot count sequence.
References Cited (Backward Citations)
US3551600A
Cited
US3742147A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-01 | 1979-12-01 | 1980-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-01 | 1983-12-01 | 1984-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-01 | 1987-12-01 | 1988-06-01 | $7700.00 | Window Closed / Lapsed |