US3306984A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Elimination of talk-off in in-band signaling systems
Assignee: AT&T Inc
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Filing: 1963-12-16
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Granted: 1967-02-28
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Expires: 1983-12-16
Abstract
No abstract record available.
Inventors
- 👤 Donald J Leonard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 00:04
CPC Classifications
H; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/44; H04Q1/444; H04Q1/446; H04Q1/4465
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
172 words
IN A TELEPHONE SYSTEM FOR SENDING COMPLEX VOICEFREQUENCY MESSAGE WAVES OCCUPYING A PREDETERMINED FREQUENCY BAND OVER A TELEPHONE TRUNK FROM A TRANSMITTING TERMINAL TO A RECEIVING TERMINAL, MEANS AT SAID TRANSMITTING TERMINAL TO TRANSMIT A SUBSTANTIALLY SINGLE-FREQUENCY TONE WITHIN SAID FREQUENCY BAND OVER SAID TRUNK TO SAID RECEIVING TERMINAL TO SIGNAL THAT THE TRUNK IS IDLE, MEANS AT SAID RECEIVING TERMINAL TO DETECT SAID TONE, A FILTER AT SAID TRANSMITTING TERMINAL TO REDUCE RELATIVE TO ENERGY AT OTHER FREQUENCIES IN SAID FREQUENCY BAND ANY ENERGY IN SAID MESSAGE WAVES AT THE FREQUENCY OF SAID TONE, AND A COMPLEMENTARY TUNED AMPLIFIER AT SAID RECEIVING TERMINAL TO INCREASE BY A CORRESPONDING AMOUNT RELATIVE TO THE ENERGY AT OTHER FREQUENCIES IN SAID FREQUENCY BAND ANY ENERGY IN THE RECEIVED MESSAGE WAVES AT THE FREQUENCY OF SAID TONE, WHEREBY ANY ENERGY IN SAID MESSAGE WAVES AT THE FREQUENCY OF SAID TONE IS PREVENTED FROM GENERATING A FALSE TRUNK-IDLE INDICATION AT SAID RECEIVING TERMINAL AND DISTURBANCE OF THE SUBSTANTIALLY SMOOTH TRANSMISSION CHARACTERISTIC OF THE TRUNK IS AVOIDED.
Claim 2
Dependent Claim
172 words
IN A TELEPHONE SYSTEM FOR SENDING COMPLEX VOICEFREQUENCY MESSAGE WAVES OCCUPYING A PREDETERMINED FREQUENCY BAND OVER A TELEPHONE TRUNK FROM A TRANSMITTING TERMINAL TO A RECEIVING TERMINAL, MEANS AT SAID TRANSMITTING TERMINAL TO TRANSMIT A SUBSTANTIALLY SINGLE-FREQUENCY TONE WITHIN SAID FREQUENCY BAND OVER SAID TRUNK TO SAID RECEIVING TERMINAL TO SIGNAL THAT THE TRUNK IS IDLE, MEANS AT SAID RECEIVING TERMINAL TO DETECT SAID TONE, A FILTER AT SAID TRANSMITTING TERMINAL TO REDUCE RELATIVE TO ENERGY AT OTHER FREQUENCIES IN SAID FREQUENCY BAND ANY ENERGY IN SAID MESSAGE WAVES AT THE FREQUENCY OF SAID TONE, AND A COMPLEMENTARY TUNED AMPLIFIER AT SAID RECEIVING TERMINAL TO INCREASE BY A CORRESPONDING AMOUNT RELATIVE TO THE ENERGY AT OTHER FREQUENCIES IN SAID FREQUENCY BAND ANY ENERGY IN THE RECEIVED MESSAGE WAVES AT THE FREQUENCY OF SAID TONE, WHEREBY ANY ENERGY IN SAID MESSAGE WAVES AT THE FREQUENCY OF SAID TONE IS PREVENTED FROM GENERATING A FALSE TRUNK-IDLE INDICATION AT SAID RECEIVING TERMINAL AND DISTURBANCE OF THE SUBSTANTIALLY SMOOTH TRANSMISSION CHARACTERISTIC OF THE TRUNK IS AVOIDED.
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) | 1970-02-27 | 1970-08-29 | 1971-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-02-27 | 1974-08-29 | 1975-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-02-27 | 1978-08-29 | 1979-02-28 | $7700.00 | Window Closed / Lapsed |