US4239935A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ringing generator
Assignee: AT&T Inc
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Filing: 1979-04-27
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Granted: 1980-12-16
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Expires: 1999-04-27
Abstract
Abstract A ringing signal generator is disclosed for remotely generating telephone ringing signals having a trapezoidal waveform. A single capacitor and two constant current sources control the wave shape while current limiting is provided on both the positive going and negative going half-cycles of the ringing signal. A voltage offset is provided between the ringing signal source and the subscriber line to prevent loading the ringing signal with the subscriber line feed circuit.
Inventors
- 👤 Barry S. Bosik
- 👤 Frank P. Tuhy, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:37
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02; H04M19/04
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
39 words
A ringing signal generator for operating telephone ringers CHARACTERIZED BY a capacitor, means for alternately and linearly charging and discharging said capacitor, and means responsive to said capacitor charging means for supplying trapezoidal ringer signals to said telephone line.
Claim 2
Dependent Claim
39 words
A ringing signal generator for operating telephone ringers CHARACTERIZED BY a capacitor, means for alternately and linearly charging and discharging said capacitor, and means responsive to said capacitor charging means for supplying trapezoidal ringer signals to said telephone line.
Claim 3
Dependent Claim
26 words
The ringing signal generator according to claim 1 further CHARACTERIZED IN THAT said charging and discharging means comprises at least two alternately enabled constant current sources.
Claim 4
Dependent Claim
26 words
The ringing signal generator according to claim 1 further CHARACTERIZED BY a zener diode connected in series between said ringing signal generator and said telephone ringers.
Claim 5
Dependent Claim
35 words
The ringing signal generator according to claim 1 further CHARACTERIZED BY current limiting means responsive to the current from said supplying means to disable said current supplying means when said current exceeds a preselected threshold.
Claim 6
Dependent Claim
73 words
A ringing generator for operating telephone ringers connected to a telephone line CHARACTERIZED BY a source of direct current voltage, a first low impedance switching means for connecting said line to said source, a second low impedance switching means for connecting said line to ground potential, a capacitor coupled to alternately supply operating and disabling currents to each of said switching means, and constant current means for alternately charging and discharging said capacitor.
Claim 7
Dependent Claim
73 words
A ringing generator for operating telephone ringers connected to a telephone line CHARACTERIZED BY a source of direct current voltage, a first low impedance switching means for connecting said line to said source, a second low impedance switching means for connecting said line to ground potential, a capacitor coupled to alternately supply operating and disabling currents to each of said switching means, and constant current means for alternately charging and discharging said capacitor.
Claim 8
Dependent Claim
21 words
The ringing generator according to claim 5 further CHARACTERIZED BY a zener diode connected between said switching means and said line.
Claim 9
Dependent Claim
20 words
The ringing generator according to claim 5 further CHARACTERIZED BY separate current limiting means for each of said switching means.
Claim 10
Dependent Claim
21 words
The ringing generator according to claim 5 further CHARACTERIZED BY unidirectional conducting means connected to isolate said capacitor from said line.
Claim 11
Dependent Claim
25 words
A remote ringing supply for telephone subscriber pair gain systems CHARACTERIZED BY a trapezoidal wave generator, and voltage gating means responsive to said wave generator.
Claim 12
Dependent Claim
25 words
A remote ringing supply for telephone subscriber pair gain systems CHARACTERIZED BY a trapezoidal wave generator, and voltage gating means responsive to said wave generator.
Claim 13
Dependent Claim
22 words
The remote ringing supply according to claim 9 further CHARACTERIZED IN THAT said wave generator comprises a capacitor and two constant sources.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-16 | 1984-06-16 | 1984-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-16 | 1988-06-16 | 1988-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-16 | 1992-06-16 | 1992-12-16 | $7700.00 | Window Closed / Lapsed |