US3886321A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ringing generator for telephone station terminal
Assignee: SEISCOR Inc
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Filing: 1973-11-05
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Granted: 1975-05-27
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Expires: 1993-11-05
Abstract
Abstract In the preferred embodiment of the invention disclosed herein, a ringing voltage generator responsive to a 300 Hz modulated carrier wave and powered by a local power supply is provided at carrier telephone system subscriber station terminal. Time constant means are provided within the ringing voltage generator to prevent sporadic ringing voltage pulses being generated in response to noise impulses on the telephone cable. Biasing means are provided for deactivating the ringing voltage generator when the telephone handset is off its hook.
Inventors
- 👤 Lester Q Krasin
- 👤 Robert D Mccallum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:33
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02; H04M19/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
90 words
A ringing voltage generator for activating a telephone bell for a carrier telephone station terminal comprising: an oscillator adapted to oscillate in response to a ringing tone signal; means cooperating with said oscillator for delaying onset of oscillations for a predetermined time interval following the onset of the tone signal; means responsive to said oscillator for switching a power supply voltage on and off to form a pulsating current for activating the telephone bell; and means for disabling the oscillator whenever the station terminal telephone is in an off-hook condition.
Claim 2
Dependent Claim
90 words
A ringing voltage generator for activating a telephone bell for a carrier telephone station terminal comprising: an oscillator adapted to oscillate in response to a ringing tone signal; means cooperating with said oscillator for delaying onset of oscillations for a predetermined time interval following the onset of the tone signal; means responsive to said oscillator for switching a power supply voltage on and off to form a pulsating current for activating the telephone bell; and means for disabling the oscillator whenever the station terminal telephone is in an off-hook condition.
Claim 3
Dependent Claim
16 words
A ringing generator is accordance with claim 1 wherein the oscillator is a square wave oscillator.
Claim 4
Dependent Claim
26 words
A ringing voltage generator in accordance with claim 1 wherein the means for delaying onset of oscillations is an integrating amplifier having a predetermined time constant.
Claim 5
Dependent Claim
52 words
A ringing voltage generator in accordance with claim 1 wherein the means for switching power supply voltage comprises a first inverter and a second inverter driving a first transistor switch and a second transistor switch respectively and having the inverters arranged to cause the first and second transistor switches to conduct alternately.
Claim 6
Dependent Claim
63 words
A ringing generator according to claim 1 wherein the means for disabling the oscillator is a transistor connected from a ringing tone signal input lead to a circuit ground and having its base connected to a source of station terminal transmitter operating power whereby the tone signal input lead is shorted to ground whenever operating power is applied to the station terminal transmitter.
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) | 1978-05-26 | 1978-11-25 | 1979-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-26 | 1982-11-25 | 1983-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-26 | 1986-11-25 | 1987-05-27 | $7700.00 | Window Closed / Lapsed |