US3829619A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone ring trip circuit
Assignee: Telent Technologies Services Ltd
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Filing: 1972-12-29
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Granted: 1974-08-13
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Expires: 1992-12-29
Abstract
Abstract A telephone ring trip circuit utilizes a pair of unidirectional current detectors poled opposite one another in a parallel arrangement which is in series with a ringing path for providing signals proportional to the currents therethrough and a pair of integrating circuits in combination with other circuitry responsive to the signals for generating a ring trip control signal when DC current flows through the path upon answering of the call.
Inventors
- 👤 S Close
- 👤 J Cordovani
- 👤 W Shaffer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:20
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02; H04M19/026
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
168 words
A telephone ring trip circuit comprising: a pair of current detectors, each having a unidirectional current path input circuit and an output circuit electrically isolated therefrom which is energized from a DC source, wherein the conductivity state of said output circuit is proportional to the current through its associated input circuit; circuit means for connecting both of said input circuits in parallel with each other and in series with a telephone ringing path arranged so that each is poled for conducting current in a direction opposite to that of the other; a pair of integrating circuits, each being connected to an output circuit of one of said current detectors, for developing a signal which is substantially related to the integral of the time function of the current therethrough; a comparator circuit responsive to said signals for generating a monitor signal proportional to the magnitude difference therebetween, and a threshold circuit connected to said comparator circuit for generating a control signal when said monitor signal exceeds a predetermined value.
Claim 2
Dependent Claim
168 words
A telephone ring trip circuit comprising: a pair of current detectors, each having a unidirectional current path input circuit and an output circuit electrically isolated therefrom which is energized from a DC source, wherein the conductivity state of said output circuit is proportional to the current through its associated input circuit; circuit means for connecting both of said input circuits in parallel with each other and in series with a telephone ringing path arranged so that each is poled for conducting current in a direction opposite to that of the other; a pair of integrating circuits, each being connected to an output circuit of one of said current detectors, for developing a signal which is substantially related to the integral of the time function of the current therethrough; a comparator circuit responsive to said signals for generating a monitor signal proportional to the magnitude difference therebetween, and a threshold circuit connected to said comparator circuit for generating a control signal when said monitor signal exceeds a predetermined value.
Claim 3
Dependent Claim
32 words
The ring trip circuit of claim 1 wherein said predetermined value corresponds to the maximum magnitude difference attainable when the ringing signal is present in the absence of any DC current flow.
Claim 4
Dependent Claim
40 words
The ring trip circuit of claim 1 wherein said current detector is a solid state device whose input circuit radiates energy proportional to the current therethrough which is applied to its associated output circuit for controlling the conductivity state thereof.
Claim 5
Dependent Claim
38 words
The ring trip circuit of claim 3 wherein said current detector is an optoelectric coupler and said input circuit includes a light emitting diode thereof and said output circuit includes the collector-emitter path of a photosensitive transistor thereof.
Claim 6
Dependent Claim
65 words
The ring trip circuit of claim 4 wherein said circuit means includes an individual resistor and diode connected in series with each of said light emitting diodes and an individual Zener diode connected across the series combination of light emitting diode and resistor having a breakdown voltage equal to the voltage across said series combination at the maximum design current for said light emitting diode.
Claim 7
Dependent Claim
54 words
The ring trip circuit of claim 4 wherein each of said integrating circuits includes a capacitor connected in parallel with a leakage resistor, both being connected in series with the collector-emitter path of the associated current detector through a charging resistor whereby the signal applied to said comparator circuit is developed across said capacitor.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-12 | 1978-02-11 | 1978-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-12 | 1982-02-11 | 1982-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-12 | 1986-02-11 | 1986-08-13 | $7700.00 | Window Closed / Lapsed |