Patent US4370526A successfully refreshed from Google Patents.
US4370526A
Expired / Lapsed
US
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Arrangement for applying a ringing voltage to a subscriber's line
Assignee: USPHILIPS Corp 100 EAST 42ND ST NEW YORK10017
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Filing: 1981-02-02
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Granted: 1983-01-25
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Expires: 2001-02-02
Abstract
Abstract When electronic circuits are used for applying a conventional ringing voltage which has been superimposed on the conventional supply voltage, they require a high supply voltage. According to the invention an a.c. voltage is used in which that portion of each period in which the polarity is positive differs from the portion in which the polarity is negative. This a.c. voltage has a DC-component by means of which the condition of the subscriber's loop can be detected. The peak-peak value of the ringing voltage may be twice the maximum permissible voltage swing of a wire of the subscriber's line, which is an optimum.
Inventors
- 👤 Franciscus A. C. M. Schoofs
- 👤 Aloysius J. Nijman
- 👤 Frederik van Dongen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:03
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02; H04M19/023
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
184 words
An arrangement for applying a combination of a d.c. voltage signal and a low-frequency a.c. voltage signal to a subscriber's line of an automatic telephony system, the low-frequency a.c. voltage signal being used to actuate a ringing device forming part of the subscriber's apparatus, comprising a low-frequency a.c. voltage generator from which two low-frequency a.c. voltages are derived which are applied in anti-phase phases to different wires of the subscriber's line, characterized in that means have been provided for forming the two low-frequency a.c. voltages such that the low-frequency a.c. voltage between the wires has a waveform in which the portion of each period during which the said low-frequency a.c. voltage is positive with respect to the mean level of the said low-frequency a.c. voltage differs from the portion during which the said low-frequency a.c. voltage is negative, the mean level being located halfway between the extreme values of the said low-frequency a.c. voltage, as a result of which the low-frequency a.c. voltage between the wires of the subscriber's line has a direct current component which may be used as the d.c. voltage signal.
Claim 2
Dependent Claim
184 words
An arrangement for applying a combination of a d.c. voltage signal and a low-frequency a.c. voltage signal to a subscriber's line of an automatic telephony system, the low-frequency a.c. voltage signal being used to actuate a ringing device forming part of the subscriber's apparatus, comprising a low-frequency a.c. voltage generator from which two low-frequency a.c. voltages are derived which are applied in anti-phase phases to different wires of the subscriber's line, characterized in that means have been provided for forming the two low-frequency a.c. voltages such that the low-frequency a.c. voltage between the wires has a waveform in which the portion of each period during which the said low-frequency a.c. voltage is positive with respect to the mean level of the said low-frequency a.c. voltage differs from the portion during which the said low-frequency a.c. voltage is negative, the mean level being located halfway between the extreme values of the said low-frequency a.c. voltage, as a result of which the low-frequency a.c. voltage between the wires of the subscriber's line has a direct current component which may be used as the d.c. voltage signal.
Claim 3
Dependent Claim
22 words
An arrangement as claimed in claim 1, characterized in that the low-frequency a.c. voltage varies trapezoidally during each portion of the period.
Claim 4
Dependent Claim
20 words
An arrangement as claimed in claim 1, characterized in that the low-frequency a.c. voltage has an asymmetric truncated sinusoidal waveform.
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) | 1986-01-24 | 1986-07-26 | 1987-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-24 | 1990-07-26 | 1991-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-24 | 1994-07-26 | 1995-01-25 | $7700.00 | Window Closed / Lapsed |