Patent US3601551A successfully refreshed from Google Patents.
US3601551A
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Tone generator control circuit
Assignee: GTE Automatic Electric Laboratories Inc
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Filing: 1968-07-31
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Granted: 1971-08-24
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Expires: 1988-07-31
Abstract
Abstract A circuit for controlling the application of precise tones to telephone lines for signaling purposes in a telephone switching system. Two or more tone generators are employed to share the total load presented with the present control circuit automatically switching, upon generator failure, the load associated with the inoperative generator to another generator, except when tone signal failure is induced by conditions such as shorting or grounding of the load.
Inventors
- 👤 Vernon F Weber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:33
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
181 words
In a telephone system, a plurality of tone-signaldistributing subsystems connected in an endless ring, each subsystem including, a plurality of circuit connections to a preceding subsystem, a plurality of circuit connections to a succeeding subsystem, a tone signal generator, a load circuit, and a control circuit connected between said tone signal generator and said load circuit, said control circuit including: tone signal detection means connected to said included generator, operated in response to tone signals from said generator to complete a circuit connection for transmission of tone signals from said included generator to said included load circuit; and transfer means connected to said detection means of a preceding subsystem, operated in response to said preceding subsystem detection means detecting an absence of tone from said preceding subsystem generator, to complete a circuit connection for transmission of tone signals from said included generator to said preceding subsystem load circuit; each of said transfer means inhibited from completing said circuit connection between said included generator and said preceding subsystem load circuit, in response to a short circuit across said preceding subsystem load circuit.
Claim 2
Dependent Claim
181 words
In a telephone system, a plurality of tone-signaldistributing subsystems connected in an endless ring, each subsystem including, a plurality of circuit connections to a preceding subsystem, a plurality of circuit connections to a succeeding subsystem, a tone signal generator, a load circuit, and a control circuit connected between said tone signal generator and said load circuit, said control circuit including: tone signal detection means connected to said included generator, operated in response to tone signals from said generator to complete a circuit connection for transmission of tone signals from said included generator to said included load circuit; and transfer means connected to said detection means of a preceding subsystem, operated in response to said preceding subsystem detection means detecting an absence of tone from said preceding subsystem generator, to complete a circuit connection for transmission of tone signals from said included generator to said preceding subsystem load circuit; each of said transfer means inhibited from completing said circuit connection between said included generator and said preceding subsystem load circuit, in response to a short circuit across said preceding subsystem load circuit.
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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) | 1974-08-23 | 1975-02-22 | 1975-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-23 | 1979-02-22 | 1979-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-23 | 1983-02-22 | 1983-08-24 | $7700.00 | Window Closed / Lapsed |