US1680367A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Repeater circuits
Assignee: AT&T Inc
•
Filing: 1922-07-07
•
Granted: 1928-08-14
•
Expires: 1942-07-07
Abstract
No abstract record available.
Inventors
- 👤 Charles S Demarest
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:25
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/02
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) | 1931-08-14 | 1932-02-13 | 1932-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1935-08-14 | 1936-02-13 | 1936-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1939-08-14 | 1940-02-13 | 1940-08-14 | $7700.00 | Window Closed / Lapsed |