Patent US4733989A successfully refreshed from Google Patents.
US2851685A
Expired / Lapsed
US
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Duplex radio communication
Assignee: RADIO PATENTS Co
•
Filing: 1954-05-25
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Granted: 1958-09-09
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Expires: 1974-05-25
Abstract
No abstract record available.
Inventors
- 👤 Hans E Hollmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:11
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/54; H04B1/56
Claims Analysis
Total Claims: 0
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-09-08 | 1962-03-10 | 1962-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-09-08 | 1966-03-10 | 1966-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-09-08 | 1970-03-10 | 1970-09-09 | $7700.00 | Window Closed / Lapsed |