US4060698A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital switching center
Assignee: Post Office
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Filing: 1976-05-11
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Granted: 1977-11-29
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Expires: 1996-05-11
Abstract
Abstract A switching center having a plurality of sets of buffer stores for connecting the channels of a plurality of pulse code modulated signal systems to the inputs of a multiplexer in which there is provided a unit for generating a false busy signal to prevent the reading of a buffer store at a time close to the time of writing into the store to reduce the possibility of simultaneous reading and writing and the consequent corruption of information.
Inventors
- 👤 Peter Alexander Birnie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:58
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
186 words
A digital switching centre having a first set of signal stores connected to receive the signals of a set of pulse code modulation (P.C.M.) signal systems respectively, each signal store having a plurality of registers for storing signals of a respective plurality of channels of the particular PCM signal system, a control means and a switching means responsive to the control means and connected to derive signals from the signal stores of the first set at selected times so as to establish selected signal transfer paths from registers of the signal stores, wherein there is provided means responsive to signals from the particular PCM signal system for producing an indication of the time of occurrence of a selected channel of the system, the control means being responsive to the indication to prevent the establishment of a particular signal transfer path from the register for storing signals from the selected channel if that path would result in there being less than a predetermined interval of time between the reception of signals by and the derivation of signals from the register for storing signals from the selected channel.
Claim 2
Dependent Claim
186 words
A digital switching centre having a first set of signal stores connected to receive the signals of a set of pulse code modulation (P.C.M.) signal systems respectively, each signal store having a plurality of registers for storing signals of a respective plurality of channels of the particular PCM signal system, a control means and a switching means responsive to the control means and connected to derive signals from the signal stores of the first set at selected times so as to establish selected signal transfer paths from registers of the signal stores, wherein there is provided means responsive to signals from the particular PCM signal system for producing an indication of the time of occurrence of a selected channel of the system, the control means being responsive to the indication to prevent the establishment of a particular signal transfer path from the register for storing signals from the selected channel if that path would result in there being less than a predetermined interval of time between the reception of signals by and the derivation of signals from the register for storing signals from the selected channel.
Claim 3
Dependent Claim
123 words
A centre according to claim 1 wherein the control means includes means for searching among suitable signal transfer paths to select a path for effecting a desired signal connection and means for producing a busy signal if a particular signal transfer path is not available, the searching means being responsive to a busy signal so as not to select a signal transfer path which is not available, the means for producing an indication producing a false busy signal to prevent the searching means from selecting a signal transfer path which would result in there being less than the predetermined interval of time between the reception of signals by and the derivation of signals from the register for storing signals from the selected channel.
Claim 4
Dependent Claim
116 words
A centre according to claim 2 wherein the switching means includes a plurality of multiplexers, a space switch connected to receive the outputs of the multiplexers and a plurality of demultiplexers having inputs connected to the space switch, the inputs of the multiplexers being connected to receive via signal stores the signals of respective P.C.M. signal systems, the outputs of the demultiplexers being arranged to provide the signals for respective outgoing P.C.M. signal systems, and the control means being arranged to establish a repeating cycle of different signal paths from inputs of multiplexers through the space switch to outputs of demultiplexers, each signal path carrying the signals of a particular channel of a P.C.M. signal system.
Claim 5
Dependent Claim
26 words
A centre according to claim 3 wherein a plurality of means for producing a false busy signal are provided respectively associated with the plurality of multiplexers.
Claim 6
Dependent Claim
42 words
A centre according to claim 2 wherein the means for producing an indication includes multi-stage counting means for clock pulses and means responsive to the outputs of a plurality of the stages of the counting means to produce the false busy signal.
Claim 7
Dependent Claim
73 words
A centre according to claim 5 including means for setting an initial state dependent on the time slot of the selected channel into the counting means and means for controlling the application of clock pulses to the counting means in dependence upon a reference time of the P.C.M. system to which the selected channel belongs, whereby the counting means stores a predetermined total when the register for the selected channel is receiving signals.
Claim 8
Dependent Claim
35 words
A centre according to claim 6 wherein the predetermined total is zero and means is provided for reversing the sense of counting of the counting means when the total in the counting means reaches zero.
References Cited (Backward Citations)
US3959588A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-11-28 | 1981-05-30 | 1981-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-28 | 1985-05-30 | 1985-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-28 | 1989-05-30 | 1989-11-29 | $7700.00 | Window Closed / Lapsed |