US3626100A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Subscriber subset for a pcm-loop system
Assignee: International Standard Electric Corp
•
Filing: 1969-05-21
•
Granted: 1971-12-07
•
Expires: 1989-05-21
Abstract
Abstract A subset for use in a pulse code modulated telephone system is provided which system employs a transmission loop with subscriber subsets serially inserted into said loop at various points along its length. The subset encodes signals within itself through use of gating and shift register circuits. Means are provided to disconnect a subset and keep the loop closed in the event of power failure in a subset.
Inventors
- 👤 Joseph Hood Mcneilly
- 👤 Roger Alan Manship
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:29
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/02; H04M9/022; H04M9/025
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
132 words
Subscriber subsets for a PCM telephone system employing a line in the form of a continuous loop in which the loop passes through and is connected to each of a plurality of subscriber subsets, the subsets each comprising a shift register coupled to the loop to record the received signals, a station number detector coupled to the shift register for determining from signals in the shift register when a subscriber subset is being called, means for applying signals generated in a called subset for replacement of signals in the shift register, switching means for coupling signals from the shift register out to the loop and timing means associated with said switching means to receive the signals from the shift register and to retime the signals before they are applied to the loop.
Claim 2
Dependent Claim
132 words
Subscriber subsets for a PCM telephone system employing a line in the form of a continuous loop in which the loop passes through and is connected to each of a plurality of subscriber subsets, the subsets each comprising a shift register coupled to the loop to record the received signals, a station number detector coupled to the shift register for determining from signals in the shift register when a subscriber subset is being called, means for applying signals generated in a called subset for replacement of signals in the shift register, switching means for coupling signals from the shift register out to the loop and timing means associated with said switching means to receive the signals from the shift register and to retime the signals before they are applied to the loop.
Claim 3
Dependent Claim
53 words
A subset according to claim 1 including first and second signal storage means, means for transferring all the incoming line signals from the shift register in parallel to the first storage means, and means for transferring the signals generated in the subset from the second storage means for storage in the shift register.
Claim 4
Dependent Claim
54 words
A subset according to claim 1 including means for determining the presence in the incoming signals of certain signals of particular significance occurring when the subset is not locked onto any channel, and means for transferring all the signals available from the shift register to said means for determining the presence of such signals.
Claim 5
Dependent Claim
56 words
A subset according to claim 1 in which the timing means includes a flip-flop and the switching means applies all signals appearing at the output of the subset to the flip-flop, whether the signals originate in the subset or are existing incoming line signals, and means applying the output of the flip-flop to the outgoing line.
Claim 6
Dependent Claim
72 words
A subscriber subset for a PCM telephone system as claimed in claim 1 and including a relay inserted in the loop the contacts of which are set to bypass the subscriber subset when the relay power supply fails, the operating coil of the relay being connected across the power supply in the subset, the voltage necessary for holding the relay being within the voltage range required for normal operation of the subset.
Claim 7
Dependent Claim
24 words
A subset according to claim 5 wherein the relay is a four-pole changeover relay, the subset being connected thereby to a balanced transmission line.
Claim 8
Dependent Claim
48 words
A subset according to claim 5 in which the relay operating characteristics are such that the relay will pull-in when the power supply voltage exceeds 90 percent of its correct value and will drop out when the power supply voltage falls below 60 percent of its correct value.
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) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |