Patent US2547539A successfully refreshed from Google Patents.
US2547539A
Expired / Lapsed
US
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Signal wave duplexing system
Assignee: AT&T Inc
•
Filing: 1946-06-27
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Granted: 1951-04-03
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Expires: 1966-06-27
Abstract
No abstract record available.
Inventors
- 👤 Douglas H Ring
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:17
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/03; G01S7/034; H; H01; H01J; H01J17/00; H01J17/02; H01J17/04; H01P; H01P1/00; H01P1/10; H01P1/12; H01P1/122
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2362561A
Cited
US2412161A
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US2396044A
Cited
US2412315A
Cited
US2425379A
Cited
US2422190A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-04-02 | 1954-10-02 | 1955-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-04-02 | 1958-10-02 | 1959-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-04-02 | 1962-10-02 | 1963-04-03 | $7700.00 | Window Closed / Lapsed |