US2767250A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic telephone exchange
Assignee: North Electric Co
•
Filing: 1952-03-13
•
Granted: 1956-10-16
•
Expires: 1972-03-13
Abstract
No abstract record available.
Inventors
- 👤 James M Blackhall
- 👤 William H Blashfield
- 👤 Dorsey D Simmons
- 👤 Maurice G Ryon
- 👤 Clarence C Crow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:33
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/0008
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1626034A
Cited
US1944693A
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US2292183A
Cited
US2486231A
Cited
US2542954A
Cited
US2621257A
Cited
US2552799A
Cited
US2617888A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-10-16 | 1960-04-16 | 1960-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-10-16 | 1964-04-16 | 1964-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-10-16 | 1968-04-16 | 1968-10-16 | $7700.00 | Window Closed / Lapsed |