US3536838A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Amplifier with voice- and line-switched gain controls in negative feedback path
Assignee: AT&T Inc
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Filing: 1968-10-01
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Granted: 1970-10-27
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Expires: 1988-10-01
Abstract
No abstract record available.
Inventors
- 👤 John M Noonan
- 👤 Peter O Schuh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:30
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/08; H04M9/10; H04M1/00; H04M1/60; H04M1/6008; H04M9/001
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-10-26 | 1974-04-27 | 1974-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-10-26 | 1978-04-27 | 1978-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-10-26 | 1982-04-27 | 1982-10-27 | $7700.00 | Window Closed / Lapsed |