Patent US2396990A successfully refreshed from Google Patents.
US2396990A
Expired / Lapsed
US
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Automatic line testing and switching circuits
Assignee: AT&T Inc
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Filing: 1943-12-09
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Granted: 1946-03-19
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Expires: 1963-12-09
Abstract
No abstract record available.
Inventors
- 👤 Dysart Birney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:47
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/74
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) | 1949-03-18 | 1949-09-17 | 1950-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1953-03-18 | 1953-09-17 | 1954-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1957-03-18 | 1957-09-17 | 1958-03-19 | $7700.00 | Window Closed / Lapsed |