US4056694A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone ringing detectors
Assignee: AT&T Inc
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Filing: 1976-09-17
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Granted: 1977-11-01
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Expires: 1996-09-17
Abstract
Abstract A telephone ringing signal detector is disclosed for detecting four-party fully selective superimposed ringing signals on a telephone line. Detecting these signals at the central office end of a subscriber loop carrier system permits encoding the ringing signals for transmission on the carrier system and subsequent decoding and utilization at a remote carrier terminal to control the regeneration of selective ringing signals.
Inventors
- 👤 Stephen Joseph Brolin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:00
CPC Classifications
H; H04; H04Q; H04Q5/00; H04Q5/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
48 words
A detector for alternating current signals superimposed on a preselected polarity of direct current voltage comprising an alternating current detector; a direct current polarity detector; and means for enabling the operation of said direct current detector only in the presence of an output from said alternating current detector.
Claim 2
Dependent Claim
48 words
A detector for alternating current signals superimposed on a preselected polarity of direct current voltage comprising an alternating current detector; a direct current polarity detector; and means for enabling the operation of said direct current detector only in the presence of an output from said alternating current detector.
Claim 3
Dependent Claim
16 words
The detector according to claim 1 wherein said direct current detector includes a bilateral threshold circuit.
Claim 4
Dependent Claim
20 words
The detector according to claim 1 wherein said polarity detector has a fast attack time and a slow decay time.
Claim 5
Dependent Claim
69 words
A superimposed ringing signal detector for telephone conductor pairs comprising a separate ringing signal detector connected to each of said conductors; a separate direct current polarity detector connected to each of said conductors; means for enabling each said separate polarity detector by the separate ringing signal detector connected to the same conductor; and means for combining the outputs of said separate polarity detectors into a common polarity indicating output.
Claim 6
Dependent Claim
69 words
A superimposed ringing signal detector for telephone conductor pairs comprising a separate ringing signal detector connected to each of said conductors; a separate direct current polarity detector connected to each of said conductors; means for enabling each said separate polarity detector by the separate ringing signal detector connected to the same conductor; and means for combining the outputs of said separate polarity detectors into a common polarity indicating output.
Claim 7
Dependent Claim
26 words
The superimposed ringing signal detector according to claim 4 further comprising means for enabling one, and only one, of said ringing signal detectors at a time.
Claim 8
Dependent Claim
34 words
The superimposed ringing signal detector according to claim 5 wherein said ringing signal detector enabling means includes means for providing priority to the ringing signal detector connected to a preselected one of said conductors.
Claim 9
Dependent Claim
35 words
The superimposed ringing signal detector according to claim 4 wherein said direct current polarity detectors each include at least one zener diode having a breakdown voltage exceeding the voltage on said conductor between ringing intervals.
Claim 10
Dependent Claim
18 words
The superimposed ringing signal detector according to claim 4 wherein said ringing signal detector includes a full-wave detector.
Claim 11
Dependent Claim
28 words
The superimposed ringing signal detector according to claim 4 wherein said polarity detector includes at least one semiconductor switch biased from the output of said ringing signal detector.
Claim 12
Dependent Claim
23 words
The superimposed ringing signal detector according to claim 4 wherein said polarity detector has a fast attack time and a slow decay time.
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) | 1980-10-31 | 1981-05-02 | 1981-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-31 | 1985-05-02 | 1985-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-31 | 1989-05-02 | 1989-11-01 | $7700.00 | Window Closed / Lapsed |