US2774890A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nonreciprocal transmitting devices
Assignee: AT&T Inc
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Filing: 1952-08-30
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Granted: 1956-12-18
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Expires: 1972-08-30
Abstract
No abstract record available.
Inventors
- 👤 Charles L Semmelman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:23
CPC Classifications
H; H03; H03C; H03C1/00; H03C1/48; G; G01; G01R; G01R21/00; G01R21/08; H03H; H03H7/00; H03H7/52
Claims Analysis
Total Claims: 0
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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) | 1959-12-18 | 1960-06-18 | 1960-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-12-18 | 1964-06-18 | 1964-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-12-18 | 1968-06-18 | 1968-12-18 | $7700.00 | Window Closed / Lapsed |