Patent US3808591A successfully refreshed from Google Patents.
US3131264A
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Multi-frequency signalling receivers
Assignee: International Standard Electric Corp
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Filing: 1961-04-05
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Granted: 1964-04-28
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Expires: 1981-04-05
Abstract
No abstract record available.
Inventors
- 👤 Chittleburgh William Fr Sidney
- 👤 Simmonds Ernest Sidney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:32
CPC Classifications
H; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/44; H04Q1/444; H04Q1/45; H04Q1/453
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
158 words
A VOICE FREQUENCY SIGNAL RECEIVER FOR RECEIVING DATA SIGNALS EACH REPRESENTED BY TWO OR MORE DIFFERENT TONES SELECTED FROM A PLURALITY OF TONES OF DIFFERENT AUDIO FREQUENCIES ARRANGED IN ORDER IN A SERIES, COMPRISING A PLURALITY OF TONE-RECEIVING CIRCUITS CORRESPONDING RESPECTIVELY TO THE SAID PLURALITY OF TONES, EACH OF SAID TONE-RECEIVING CIRCUITS INCLUDING A FILTER ADAPTED TO SELECT A TONE OF THE CORRESPONDING FREQUENCY AND AN ASSOCIATED TONE RECEIVER ADAPTED TO RESPOND TO THE SAID SELECTED TONES, COUPLING MEANS INTERCONNECTING EACH SAID TONE RECEIVER WITH THE TONE RECEIVER CORRESPONDING TO NEXT HIGHER FREQUENCY IN THE SAID SERIES OF FREQUENCIES AND WITH THE TONE RECEIVER CORRESPONDING TO THE NEXT LOWER FREQUENCY IN SAID SERIES OF FREQUENCIES, MEANS IN EACH TONE RECEIVER RESPONSIVE TO THE RECEIPT OF AN ASSOCIATED FREQUENCY FOR GENERATING AND FOR TRANSMITTING CONTROL SIGNALS OVER THE ASSOCIATED COUPLING MEANS, AND MEANS IN EACH TONE RECEIVER RECEIVING THE SAID CONTROL SIGNALS FOR REDUCING THE SENSITIVITY OF THE LAST-SAID
Claim 2
Dependent Claim
158 words
A VOICE FREQUENCY SIGNAL RECEIVER FOR RECEIVING DATA SIGNALS EACH REPRESENTED BY TWO OR MORE DIFFERENT TONES SELECTED FROM A PLURALITY OF TONES OF DIFFERENT AUDIO FREQUENCIES ARRANGED IN ORDER IN A SERIES, COMPRISING A PLURALITY OF TONE-RECEIVING CIRCUITS CORRESPONDING RESPECTIVELY TO THE SAID PLURALITY OF TONES, EACH OF SAID TONE-RECEIVING CIRCUITS INCLUDING A FILTER ADAPTED TO SELECT A TONE OF THE CORRESPONDING FREQUENCY AND AN ASSOCIATED TONE RECEIVER ADAPTED TO RESPOND TO THE SAID SELECTED TONES, COUPLING MEANS INTERCONNECTING EACH SAID TONE RECEIVER WITH THE TONE RECEIVER CORRESPONDING TO NEXT HIGHER FREQUENCY IN THE SAID SERIES OF FREQUENCIES AND WITH THE TONE RECEIVER CORRESPONDING TO THE NEXT LOWER FREQUENCY IN SAID SERIES OF FREQUENCIES, MEANS IN EACH TONE RECEIVER RESPONSIVE TO THE RECEIPT OF AN ASSOCIATED FREQUENCY FOR GENERATING AND FOR TRANSMITTING CONTROL SIGNALS OVER THE ASSOCIATED COUPLING MEANS, AND MEANS IN EACH TONE RECEIVER RECEIVING THE SAID CONTROL SIGNALS FOR REDUCING THE SENSITIVITY OF THE LAST-SAID
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) | 1967-04-28 | 1967-10-28 | 1968-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-04-28 | 1971-10-28 | 1972-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-04-28 | 1975-10-28 | 1976-04-28 | $7700.00 | Window Closed / Lapsed |