Patent US2045224A successfully refreshed from Google Patents.
US2045224A
Expired / Lapsed
US
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Duplex communication system
Assignee: MEAF Machinerieen en Apparaten Fabrieken NV
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Filing: 1932-11-07
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Granted: 1936-06-23
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Expires: 1952-11-07
Abstract
No abstract record available.
Inventors
- 👤 Gerhard Ernst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:11
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/54; H04B1/56
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) | 1939-06-23 | 1939-12-23 | 1940-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1943-06-23 | 1943-12-23 | 1944-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1947-06-23 | 1947-12-23 | 1948-06-23 | $7700.00 | Window Closed / Lapsed |