US2379069A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic line testing and switching circuits
Assignee: AT&T Inc
•
Filing: 1943-07-24
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Granted: 1945-06-26
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Expires: 1963-07-24
Abstract
No abstract record available.
Inventors
- 👤 Dysart Birney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:44
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/22; H04M3/26; H04M3/28; H04M3/32; H04M3/40
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) | 1948-06-25 | 1948-12-25 | 1949-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1952-06-25 | 1952-12-25 | 1953-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1956-06-25 | 1956-12-25 | 1957-06-26 | $7700.00 | Window Closed / Lapsed |