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Patent US2775740A successfully refreshed from Google Patents.
US2775740A
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Directional coupling systems
Assignee: AT&T Inc
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Filing: 1950-11-02
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Granted: 1956-12-25
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Expires: 1970-11-02
Abstract
No abstract record available.
Inventors
- 👤 Bernard M Oliver
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:09
CPC Classifications
H; H01; H01P; H01P5/00; H01P5/12; H01P5/16; H01P5/18
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1853181A
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US2159648A
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US2527979A
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US2606974A
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US2575571A
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US2560806A
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US2523173A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-12-25 | 1960-06-25 | 1960-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-12-25 | 1964-06-25 | 1964-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-12-25 | 1968-06-25 | 1968-12-25 | $7700.00 | Window Closed / Lapsed |