US3586782A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telecommunication loop system
Assignee: STC PLC
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Filing: 1968-09-30
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Granted: 1971-06-22
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Expires: 1988-09-30
Abstract
Abstract A communication network is described in which a group of subscribers have access to a unidirectional closed loop transmission line arranged for the continuous unidirectional circulation of TDM PCM signals. Subscribers on the same closed loop line communicate by seizing a free time slot in the TDM sequence. Association of one closed loop line with another through signal transfer centers sets up longer links through two or more closed loop lines. The network can handle coded data, television, facsimile or the like in addition to coded speech.
Inventors
- 👤 David Lane Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:44
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
237 words
A telecommunication system comprising: a closed-loop unidirectional transmission line; first means coupled to said closed-loop line for providing thereon a plurality of time division multiplexed communication channels; and a plurality of subscriber stations each including second means to connect that one of said subscriber''s stations to said closed-loop line to establish communication on an unused one of said channels with an idle one of said subscriber stations: said first means including third means for generating sync signals on one of said channels and empty channel indicating signals for others of said channels: said second means including signal detector means and timing means coupled to said closedloop line to enable the detection of said empty channel indicating signals for at least one unused one of said others of said channels upon initiating a call and to seize for use said unused one of said others of said channels; and said first means further including fourth means coupled to said closed-loop line for interruption thereof during the occurrence of unused channels and inserting said empty channel indicating signals into one end of said interrupted closed-loop line, and fifth means coupled to the other end of said interrupted closed loop line to detect the absence of said empty channel indicating signals indicating that said unused one of said others of said channels has been seized by one of said subscriber stations, and to remove said interruption of said closed-loop line.
Claim 2
Dependent Claim
237 words
A telecommunication system comprising: a closed-loop unidirectional transmission line; first means coupled to said closed-loop line for providing thereon a plurality of time division multiplexed communication channels; and a plurality of subscriber stations each including second means to connect that one of said subscriber''s stations to said closed-loop line to establish communication on an unused one of said channels with an idle one of said subscriber stations: said first means including third means for generating sync signals on one of said channels and empty channel indicating signals for others of said channels: said second means including signal detector means and timing means coupled to said closedloop line to enable the detection of said empty channel indicating signals for at least one unused one of said others of said channels upon initiating a call and to seize for use said unused one of said others of said channels; and said first means further including fourth means coupled to said closed-loop line for interruption thereof during the occurrence of unused channels and inserting said empty channel indicating signals into one end of said interrupted closed-loop line, and fifth means coupled to the other end of said interrupted closed loop line to detect the absence of said empty channel indicating signals indicating that said unused one of said others of said channels has been seized by one of said subscriber stations, and to remove said interruption of said closed-loop line.
Claim 3
Dependent Claim
91 words
A system according to claim 1, wherein each of said subscriber stations further include pulse-modulating and pulse-demodulating means; and each of said second means further include sixth means coupled to said signal detector means and timing means and said close loop line responsive to the initiation of a call to interrupt said closed-loop line during the first and subsequent occurrences of said seized unused one of said others of said channels and to connect the ends of said interrupted closed-loop line to the appropriate one of said pulse-modulating and pulse-demodulating means.
Claim 4
Dependent Claim
107 words
A system according to claim 2, wherein each of said signal detector means and timing means further includes seventh means coupled to said closed loop line for detecting in one of said other channels a signal unique to a particular one of said subscriber station indicating that it is being called; said sixth means coupled to said seventh means being responsive to the output thereof to interrupt said closed loop line during subsequent occurrences of said one of said other channels carrying said unique signal and connecting the ends of said interrupted closed loop line to the appropriate one of said pulse modulating and pulse modulating means.
Claim 5
Dependent Claim
58 words
A system according to claim 3, wherein said first means further includes a variable delay means coupled to said closed loop line to maintain sync between signals coupled into said closed loop line by said first means and received from said closed loop line by said first means regardless of variations in the propagation time in said system.
Claim 6
Dependent Claim
83 words
A system according to claim 4, wherein said first means further includes eighth means coupled to said closed loop line to detect a second unique signal indicating calls to be made outside said closed loop line, ninth means coupled to said eighth means being responsive to the output thereof to interrupt said closed loop line, an incoming and outgoing buffer, and tenth means coupled to said eighth means responsive to the output thereof to connect said interrupted closed loop line to said buffers.
Claim 7
Dependent Claim
102 words
A system according to claim 5, wherein said first means further includes eleventh means coupled to said incoming buffer to detect a third unique signal at the output of said incoming buffer indicating a call from an external source is being made to one of said other subscriber stations, and twelfth means coupled to said closed loop line and said eleventh means to detect and seize an unused one of said other of said channels and activate said tenth means to connect said buffers to said closed loop line during subsequent occurrences of said seized one of said other of said channels.
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) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |