US2921137A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone system
Assignee: General Dynamics Corp
•
Filing: 1952-12-16
•
Granted: 1960-01-12
•
Expires: 1972-12-16
Abstract
No abstract record available.
Inventors
- 👤 Frank A Morris
- 👤 Robert B Trousdale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:40
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2649505A
Cited
US2490833A
Cited
US2619548A
Cited
US2647163A
Cited
US2754367A
Cited
US2773935A
Cited
GB777933A
Cited
US2773939A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-01-11 | 1963-07-13 | 1964-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-01-11 | 1967-07-13 | 1968-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-01-11 | 1971-07-13 | 1972-01-12 | $7700.00 | Window Closed / Lapsed |