US3600519A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Subscriber subset for pcm telephone system
Assignee: International Standard Electric Corp
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Filing: 1969-05-21
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Granted: 1971-08-17
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Expires: 1989-05-21
Abstract
Abstract In a closed loop PCM system each subscriber''s subset functions as digital equipment for both speech and signalling. A speech coder used in the system does not go into operation until after the signalling setting up a call has been completed, consequently it is possible to use one store (shift register) for setting up the signalling codes and also as the counter forming part of the speech coder. The subset also uses a common shift register for all incoming and outgoing line signals.
Inventors
- 👤 Joseph Hood Mcneilly
- 👤 Roger Alan Manship
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:33
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/02; H04M9/022; H04M9/025
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
143 words
A subscriber subset for a PCM telephone system employing a continuous loop line comprising a first shift register into which signals in the loop are entered, means for interrupting the loop line when the subset is locked onto a time slot, means for transferring the first shift register contents to the outgoing portion of the loop line in place of the signals being received in the incoming portion of the loop line when the line is so interrupted, means for extracting all the signals received in the first shift register for transfer to either speech decoder means or station number detector means or empty channel code detector means, means for replacing the extracted signals with either a station number code or a speech code, and timing means arranged to control the entering and extraction of signals into and from the first shift register.
Claim 2
Dependent Claim
143 words
A subscriber subset for a PCM telephone system employing a continuous loop line comprising a first shift register into which signals in the loop are entered, means for interrupting the loop line when the subset is locked onto a time slot, means for transferring the first shift register contents to the outgoing portion of the loop line in place of the signals being received in the incoming portion of the loop line when the line is so interrupted, means for extracting all the signals received in the first shift register for transfer to either speech decoder means or station number detector means or empty channel code detector means, means for replacing the extracted signals with either a station number code or a speech code, and timing means arranged to control the entering and extraction of signals into and from the first shift register.
Claim 3
Dependent Claim
116 words
A subset according to claim 1 wherein the means for replacing the extracted signals includes a counter means for transferring into the counter in parallel any station number code to be called, means for inhibiting the input of speech code pulses to the counter while the number is being called and means for cancelling the station number code when the called number answers and removing the inhibition on speech codes whereby the counter receives speech code pulses in serial form and acts as a counter for the speech coder, the counts so recorded in the counter being transferred in parallel form to the first shift register for transfer to the outgoing portion of the looped line.
Claim 4
Dependent Claim
36 words
A subset according to claim 1 in which the means for interrupting the line and transferring the contents of the first shift register to the outgoing portion of the line comprises a line gate changeover switch.
Claim 5
Dependent Claim
77 words
A subset according to claim 1 in which the signals into the first shift register from the line and the signals from the first shift register to the line are transferred in a serial mode and the extraction signals from the first shift register to either the speech decoder means, station number or empty channel code detector means and the replacement thereof with either a station number code or a speech code is in a parallel mode.
Claim 6
Dependent Claim
51 words
A subset according to claim 1, including means for modifying the contents of the first shift register when signals transferred to the station number detector means cause an output therefrom, the modified contents being transferred to the outgoing portion of the line in place of the original incoming station number code.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-16 | 1975-02-15 | 1975-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-16 | 1979-02-15 | 1979-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-16 | 1983-02-15 | 1983-08-17 | $7700.00 | Window Closed / Lapsed |