US3840704A
Expired / Lapsed
US
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Time division switching system
Assignee: AT&T Inc
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Filing: 1973-10-11
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Granted: 1974-10-08
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Expires: 1993-10-11
Abstract
Abstract A time-division switching system is disclosed in which interleaved control memories are utilized to control pairs of switching modules in an implementation of slipped-mirror-image call processing apparatus and methods. The implementation provides, among other things, a simplified path hunt arrangement, uniformity of call setup, maintenance and release. The implementation also minimizes the amount of control memory and associated hardware required for call processing.
Inventors
- 👤 C Baugh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:31
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04Q11/06
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
134 words
Apparatus for establishing and maintaining a plurality of bidirectional time-division multiplexed communication paths comprising A. a first ordered plurality of time-division switching crosspoints for establishing connections in a first direction for each of two bidirectional paths, B. a second ordered plurality of time-division switching crosspoints, not necessarily mutually exclusive of said first plurality of switching crosspoints, for establishing connections in the second direction of said bidirectional paths, each of said second plurality of switching crosspoints bearing a symmetrical relation to one of said first plurality of switching crosspoints, and C. control means for selectively interconnecting said first plurality of switching crosspoints during a first time slot and for selectively interconnecting said second plurality of switching crosspoints during a second time slot, said first and second time slots being mutually exclusive but not necessarily contiguous.
Claim 2
Dependent Claim
134 words
Apparatus for establishing and maintaining a plurality of bidirectional time-division multiplexed communication paths comprising A. a first ordered plurality of time-division switching crosspoints for establishing connections in a first direction for each of two bidirectional paths, B. a second ordered plurality of time-division switching crosspoints, not necessarily mutually exclusive of said first plurality of switching crosspoints, for establishing connections in the second direction of said bidirectional paths, each of said second plurality of switching crosspoints bearing a symmetrical relation to one of said first plurality of switching crosspoints, and C. control means for selectively interconnecting said first plurality of switching crosspoints during a first time slot and for selectively interconnecting said second plurality of switching crosspoints during a second time slot, said first and second time slots being mutually exclusive but not necessarily contiguous.
Claim 3
Dependent Claim
10 words
Apparatus according to claim 1 wherein said control means comprises
Claim 4
Dependent Claim
38 words
second means responsive to said address signals for generating first and second sequences of control signals, said second sequence comprising the same set of signals as said first sequence except for the ordering of said sets of signals.
Claim 5
Dependent Claim
38 words
second means responsive to said address signals for generating first and second sequences of control signals, said second sequence comprising the same set of signals as said first sequence except for the ordering of said sets of signals.
Claim 6
Dependent Claim
88 words
Apparatus according to claim 2 wherein said second means comprises memory means storing a plurality of words, and means for reading two sequences of signals from said memory means, said means for reading comprising means for reading in said first sequence a first word of a pair of words during said first time slot and a second word during said second time slot, and means for reading in said second sequence said second word during said first time slot and said first word during said second time slot.
Claim 7
Dependent Claim
29 words
Apparatus according to claim 3 wherein said means for reading comprises means for reading said first and second words in said first and second sequences during consecutive time slots.
Claim 8
Dependent Claim
43 words
Apparatus according to claim 4 wherein said memory means comprises a plurality of locations, each capable of storing two of said words, and said means for reading comprises means for reading the contents of each location during each of two consecutive time slots.
Claim 9
Dependent Claim
59 words
Apparatus according to claim 5 wherein each of said switching crosspoints is part of a separate switching matrix and wherein said memory means comprises a plural location memory for each pair of said switching matrices, which pair of switching matrices comprises one of said first plurality of crosspoints and its symmetrical mate in said second plurality of switching crosspoints.
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) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |