Patent US3721768A successfully refreshed from Google Patents.
US3721768A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ground start adapter unit
Assignee: SAN BAR CORP
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Filing: 1971-10-04
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Granted: 1973-03-20
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Expires: 1991-10-04
Abstract
Abstract A ground start adapter unit for use with telephone systems is disclosed. The ground start adapter unit serves to enable peripheral telephone units that are designed for loop start operation to be employed with telephone systems designed for ground start operation. The unit generally operates by responding to the application of ground potential to either a tip or ring conductor from a central office or subscriber facility, respectively. A ground start adapter unit thus includes circuitry for detecting ground potential applied to either one of the conventional tip and ring conductors from either a central office or from a subscriber facility. Also included is circuitry for detecting a loop condition at the subscriber facility and circuitry for tripping the transmission of ringing signals from the central office when the subscriber facility is in an off-hook condition. A reversal circuit operates to detect any polarity reversal of the line conductors from the central office and effect a corresponding reversal of the line conductors connected to the subscriber facility.
Inventors
- 👤 F Mazac
- 👤 A Fitzsimons
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:37
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/22; H04M3/2272; H04M19/00; H04M19/001; H04M19/005
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
207 words
A ground start adapter circuit for use with telephone systems having a ground start mode of operation, the systems including a subscriber facility and a central office facility adapted to be controllably connected by a pair of line conductors through an intermediate device having a non-ground start mode of operation, said ground start adapter circuit being coupled in parallel with said intermediate device and coupled in series between said central office and subscriber facilities to adapt said intermediate device for said ground start mode of operation, said ground start adapter circuit including: first means for detecting the transmission of ground potential signals from said central office over said conductors; second means, responsive to operation of said first means, for detecting the interconnection of said line conductors at said subscriber facility by operation thereof, said second means effecting an operative connection of said central office and said subscriber facility to said intermediate device via said line conductors for a duration corresponding to the interconnection of said line conductors at said subscriber facility; and third means for providing a ring trip signal to said central office in response to the operation of said subscriber facility, said third means being deactivated by said second means after a selected time duration.
Claim 2
Dependent Claim
207 words
A ground start adapter circuit for use with telephone systems having a ground start mode of operation, the systems including a subscriber facility and a central office facility adapted to be controllably connected by a pair of line conductors through an intermediate device having a non-ground start mode of operation, said ground start adapter circuit being coupled in parallel with said intermediate device and coupled in series between said central office and subscriber facilities to adapt said intermediate device for said ground start mode of operation, said ground start adapter circuit including: first means for detecting the transmission of ground potential signals from said central office over said conductors; second means, responsive to operation of said first means, for detecting the interconnection of said line conductors at said subscriber facility by operation thereof, said second means effecting an operative connection of said central office and said subscriber facility to said intermediate device via said line conductors for a duration corresponding to the interconnection of said line conductors at said subscriber facility; and third means for providing a ring trip signal to said central office in response to the operation of said subscriber facility, said third means being deactivated by said second means after a selected time duration.
Claim 3
Dependent Claim
57 words
The adapter circuit defined by claim 1 further including: reversal detector means for detecting a selected polarity condition of the line conductors connected to the central office facility; and line reversing means responsive to said reversal detector means, for adapting the line conductors connected to the subscriber facility to have a polarity corresponding to said selected polarity.
Claim 4
Dependent Claim
88 words
The adapter circuit defined by claim 1 wherein said line conductors include central office tip and ring conductors connected to the central office facility and subscriber tip and ring conductors connected to the subscriber facility, said adapter circuit further including: reversal detector means for detecting a selected polarity reversal of said central office tip and ring conductors; and reversing means for effecting a corresponding polarity reversal of said subscriber tip and ring conductors in response to the detection of said selected polarity reversal by said reversal detector means.
Claim 5
Dependent Claim
60 words
The adapter circuit defined by claim 1 wherein said line conductors include central office tip and ring conductors connected to the central office facility and subscriber tip and ring conductors connected to the subscriber facility, said first means including a first relay connected to be enErgized in response to the presence of ground potential on said central office tip conductor.
Claim 6
Dependent Claim
55 words
The adapter circuit defined by claim 4, said second means connected to be enabled by the energization of said first relay circuit, said second means including a second relay connected to be energized in response to the interconnection of said subscriber tip and ring conductors at said subscriber facility once said second means is enabled.
Claim 7
Dependent Claim
39 words
The adapter circuit defined by claim 5 wherein said third means includes a third relay connected to be energized for selected lengths of time in response to the subscriber tip and ring conductors being interconnected at the subscriber facility.
Claim 8
Dependent Claim
55 words
The adapter circuit defined by claim 6 further including: reversal detector means for detecting selected polarity reversals of said central office tip and ring conductors; and reversing means for effecting a corresponding polarity reversal of said subscriber tip and ring conductors in response to the detection of said polarity reversals by said reversal detector means.
Claim 9
Dependent Claim
70 words
The adapter circuit defined by claim 7 wherein said reversal detector means includes a fourth relay connected to be energized in response to the presence of ground potential on said central office ring conductor, said reversing means including cross connector means responsive to the energization of said fourth relay for reversing the polarity of said subscriber tip and ring conductors to have ground potential present on the subscriber ring conductor.
Claim 10
Dependent Claim
185 words
An adapter circuit for use with telephone systems including a central office station and a subscriber station each connected by a pair of tip and ring conductors to an intermediate device, the adapter circuit being connected across the intermediate device and to the tip and ring conductors of both said stations for effecting completion of an operating connection of said stations through said intermediate device in response to the transmission of ground start signals from either of said stations, said adapter circuit including: central office means for detecting ground start signals transmitted from said central office station over a conductor connected thereto, said central office means effecting transmission of said ground start signals to said subscriber station; subscriber means, responsive to operation of said central office means, for detecting interconnection of the tip and ring conductors at the subscriber station by operation thereof, said subscriber means completing said operating connection of said stations through said intermediate device; and tripping means, responsive to operation of said subscriber means, for interconnecting the tip and ring conductors of said central office station for a predetermined period of time.
Claim 11
Dependent Claim
185 words
An adapter circuit for use with telephone systems including a central office station and a subscriber station each connected by a pair of tip and ring conductors to an intermediate device, the adapter circuit being connected across the intermediate device and to the tip and ring conductors of both said stations for effecting completion of an operating connection of said stations through said intermediate device in response to the transmission of ground start signals from either of said stations, said adapter circuit including: central office means for detecting ground start signals transmitted from said central office station over a conductor connected thereto, said central office means effecting transmission of said ground start signals to said subscriber station; subscriber means, responsive to operation of said central office means, for detecting interconnection of the tip and ring conductors at the subscriber station by operation thereof, said subscriber means completing said operating connection of said stations through said intermediate device; and tripping means, responsive to operation of said subscriber means, for interconnecting the tip and ring conductors of said central office station for a predetermined period of time.
Claim 12
Dependent Claim
50 words
The adapter circuit defined by claim 9 further including subscriber ground means for detecting ground start signals transmitted from said subscriber station over a conductor connected thereto, said subscriber ground means causing operation of said tripping means in response to detection of said ground start signals from said subscriber station.
Claim 13
Dependent Claim
59 words
The adapter circuit defined by claim 9 further including: reversal detector means for detecting a selected polarity reversal of the tip and ring conductors connected to said central office station; and reversing means, responsive to the operation of said reversal detector means, for effecting a corresponding polarity reversal of the tip and ring conductors connected to the subscriber station.
Claim 14
Dependent Claim
67 words
The adapter circuit defined by claim 9 wherein said central office means includes a first relay circuit that is connected to be responsive to the application thereto of ground start signals from said central office station, said first relay circuit including means for enabling said ground start signals from said central office station to be provided to said subscriber station upon energization of said first relay circuit.
Claim 15
Dependent Claim
47 words
The adapter circuit defined By claim 12 wherein said subscriber means includes a second relay circuit that is connected to be energized in response to a subscriber station being operated to interconnect the tip and ring conductors connected thereto concurrently with operation of said central office means.
Claim 16
Dependent Claim
55 words
The adapter circuit defined by claim 13 wherein said tripping means includes a third relay circuit that is connected to be operated for a period of time controlled by operation of said second relay circuit, operation of said third relay circuit effecting interconnection of said tip and ring conductors connected to said central office station.
Claim 17
Dependent Claim
50 words
The adapter circuit defined by claim 14 further including subscriber ground means for detecting ground start signals transmitted from said subscriber station over a conductor connected thereto, said subscriber ground means causing operation of said tripping means in response to detection of said ground start signals from said subscriber station.
Claim 18
Dependent Claim
36 words
The adapter circuit defined by claim 15 wherein said subscriber ground means includes said third relay circuit and means for energizing said third relay circuit in response to ground start signals provided from said subscriber station.
Claim 19
Dependent Claim
78 words
The adapter circuit defined by claim 16 further including: reversal detector means for detecting a selected polarity reversal of the tip and ring conductors connected to said central office station; and reversing means, responsive to operation of said reversal detector means, for effecting a polarity reversal of the tip and ring conductors connected to the subscriber station which polarity reversal corresponds to said selected polarity reversal of the tip and ring conductors connected to the central office station.
Claim 20
Dependent Claim
51 words
The adapter circuit defined by claim 17 wherein said reversal detector circuit includes a fourth relay circuit connected to be energized in response to the presence of ground potential on the ring conductor connected to the central office station, energization of said fourth relay circuit causing operation of said reversing means.
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) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |