US3978290A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital private automatic branch exchange
Assignee: Individual
•
Filing: 1974-10-08
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Granted: 1976-08-31
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Expires: 1994-10-08
Abstract
Abstract A private automatic branch exchange utilizing PCM (pulse code modulated) digital technology with a four wire non-blocking PCM network having an ability to provide a double (three port) connection for each inlet, on a digital basis is disclosed. As a result of the network various new functional arrangements are possible. The application of PCM for implementing PABX systems provides an opportunity to interface directly with a PCM trunk thereby eliminating the PCM to analog code conversion.
Inventors
- 👤 Bhupendra Nath Sarma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:54
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04J; H04J3/00; H04J3/02; H04J3/12
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
209 words
A telecommunication switching system for switching between line, trunk, and operator inlets, comprising: an input time division multiplexed highway and an output time division multiplexed highway; a four wire, non blocking digital PCM switching network having a plurality of input ports connected to said input time division multiplexed highway and a plurality of output ports connected to said output time division multiplexed highway; a plurality of line, trunk, and operator inlet interface means for forming pulse amplitude modulated (PAM) highways; means for connecting PCM trunks directly to said switching network through said input time division multiplexed highway; means for connecting PCM tones directly to said switching network through said input time division multiplexed highway; analog-to-digital conversion (ADC) means for converting said PAM highways to PCM information; means for multiplexing said PCM information from said ADC means, direct PCM trunk connecting means, and PCM tone connecting means, to form said input time division multiplexed highway; means for demultiplexing said outlet time division multiplexed highway to provide a group of channels; digital-to-analog conversion (DAC) means for providing PCM to analog code conversion of said channels; and a means for providing said four wire, non-blocking digital network with an ability to provide double connection (three port) between said plurality of input ports.
Claim 2
Dependent Claim
209 words
A telecommunication switching system for switching between line, trunk, and operator inlets, comprising: an input time division multiplexed highway and an output time division multiplexed highway; a four wire, non blocking digital PCM switching network having a plurality of input ports connected to said input time division multiplexed highway and a plurality of output ports connected to said output time division multiplexed highway; a plurality of line, trunk, and operator inlet interface means for forming pulse amplitude modulated (PAM) highways; means for connecting PCM trunks directly to said switching network through said input time division multiplexed highway; means for connecting PCM tones directly to said switching network through said input time division multiplexed highway; analog-to-digital conversion (ADC) means for converting said PAM highways to PCM information; means for multiplexing said PCM information from said ADC means, direct PCM trunk connecting means, and PCM tone connecting means, to form said input time division multiplexed highway; means for demultiplexing said outlet time division multiplexed highway to provide a group of channels; digital-to-analog conversion (DAC) means for providing PCM to analog code conversion of said channels; and a means for providing said four wire, non-blocking digital network with an ability to provide double connection (three port) between said plurality of input ports.
Claim 3
Dependent Claim
47 words
A telecommunication switching system in accordance with claim 1 wherein said four wire, non-blocking digital switching network comprises a plurality of voice memories equal in capacity to the said input ports, connection memories, counter logic, voice memory address logic, common control access logic and voice sample combiner.
Claim 4
Dependent Claim
60 words
A telecommunication switching system in accordance with claim 2 wherein the number of ports in said input time division multiplexed highway is equal to the number of words in said plurality of voice memories which are addressable by the number of bits in the plurality of connection memories for random reading and by the counter logic means for sequential writing.
Claim 5
Dependent Claim
59 words
A telecommunication switching system in accordance with claim 3 wherein said voice memories are addressed by the plurality of connection memories containing information regarding a network connection to be established, in particular a first connection memory containing the information regarding a normal two port connection and a second connection memory containing the information regarding an additional third port connection.
Claim 6
Dependent Claim
97 words
A telecommunication switching system in accordance with claim 4 wherein said three port connection arrangement comprises; a plurality of voice sample input from the input time division multiplexed highway for writing the voice memory means; a plurality of output from the voice memories obtained by addressing through said connection memories for reading; means for combining voice sample by a comparison method in said voice sample combiner circuit; a means for combining voice sample by an addition method in said voice sample combiner circuit; and a time division multiplexed highway arrangement from the said voice sample combiner circuit.
Claim 7
Dependent Claim
39 words
A telecommunication switching system in accordance with claim 5 wherein said third port connection arrangement further comprises: a voice memory address logic to address said voice memories through an address provided by said connection memories and said counter logic.
Claim 8
Dependent Claim
35 words
A telecommunication switching system in accordance with claim 1 wherein said PCM tones are available for outpulsing at the same time to all the necessary ports on the said input time division multiplexed highway arrangement.
Claim 9
Dependent Claim
46 words
A telecommunication switching system in accordance with claim 1 wherein operator functions are performed through a plurality of common control means due to the non-blocking arrangement of said four wire, non-blocking digital network with an ability to hold third party conversation in said control memory arrangement.
Claim 10
Dependent Claim
25 words
A telecommunication switching system in accordance with claim 1 wherein a network map is provided in said control memories accessable by said common control means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-31 | 1980-03-01 | 1980-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-31 | 1984-03-01 | 1984-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-31 | 1988-03-01 | 1988-08-31 | $7700.00 | Window Closed / Lapsed |