US1947621A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reverberation circuit
Assignee: AT&T Inc
•
Filing: 1932-06-14
•
Granted: 1934-02-20
•
Expires: 1952-06-14
Abstract
No abstract record available.
Inventors
- 👤 Ernst H Schreiber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:54
CPC Classifications
G; G10; G10K; G10K15/00; G10K15/08; G10K15/10; Y; Y10; Y10S; Y10S84/00; Y10S84/26
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) | 1937-02-19 | 1937-08-21 | 1938-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1941-02-19 | 1941-08-21 | 1942-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1945-02-19 | 1945-08-21 | 1946-02-20 | $7700.00 | Window Closed / Lapsed |