Patent US4862495A successfully refreshed from Google Patents.
US4862495A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telecommunications subscriber line interface circuit and party identification facility
Assignee: Telent Technologies Services Ltd
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Filing: 1988-04-22
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Granted: 1989-08-29
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Expires: 2008-04-22
Abstract
Abstract The invention provides a tip party identification facility in association with a subscriber line interface circuit. The tip party identification facility takes advantage of a shutdown feature and the output of a common mode error amplifier of the subscriber line interface circuit. The use of this facility enables the central office to determine whether the tip party or ring party is off-hook for billing purposes.
Inventors
- 👤 Michael E. Stibila
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:52
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/001; H04M19/005; H04M15/00; H04M15/36
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
171 words
A telecommunications central office including a telecommunications subscriber line interface circuit and party identification facility, comprising: a differential mode feedback circuit having a feed shut down control input, and arranged to monitor a ring line and a tip line, and generate a current output which is applied to a converter to generate a voltage output, a first amplifier arranged to monitor the ring and tip lines and generate an output which is proportional to a common-mode current flowing in the ring and tip lines when the subscriber line interface circuit is in a feed shut down mode as dictated by the output from differential mode feedback circuit, a second amplifier arranged to receive the output from the first amplifier and amplify a direct current component of the output from the first amplifier and attenuate the alternating current component of the output from the first amplifier, and, a comparator arranged to receive the amplified direct current component and compare it witl a reference voltage to determine if the tip party is off-hook.
Claim 2
Dependent Claim
171 words
A telecommunications central office including a telecommunications subscriber line interface circuit and party identification facility, comprising: a differential mode feedback circuit having a feed shut down control input, and arranged to monitor a ring line and a tip line, and generate a current output which is applied to a converter to generate a voltage output, a first amplifier arranged to monitor the ring and tip lines and generate an output which is proportional to a common-mode current flowing in the ring and tip lines when the subscriber line interface circuit is in a feed shut down mode as dictated by the output from differential mode feedback circuit, a second amplifier arranged to receive the output from the first amplifier and amplify a direct current component of the output from the first amplifier and attenuate the alternating current component of the output from the first amplifier, and, a comparator arranged to receive the amplified direct current component and compare it witl a reference voltage to determine if the tip party is off-hook.
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) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |