Patent US1999327A successfully refreshed from Google Patents.
US1999327A
Expired / Lapsed
US
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Amplifying system
Assignee: AT&T Inc
•
Filing: 1931-12-26
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Granted: 1935-04-30
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Expires: 1951-12-26
Abstract
No abstract record available.
Inventors
- 👤 William H T Holden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:36
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) | 1938-04-29 | 1938-10-29 | 1939-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1942-04-29 | 1942-10-29 | 1943-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1946-04-29 | 1946-10-29 | 1947-04-30 | $7700.00 | Window Closed / Lapsed |