US2782257A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic telephone system
Assignee: North Electric Co
•
Filing: 1951-07-23
•
Granted: 1957-02-19
•
Expires: 1971-07-23
Abstract
No abstract record available.
Inventors
- 👤 William H Blashfield
- 👤 James M Blackhall
- 👤 Oxaal Arne
- 👤 Walter J Bergman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:19
CPC Classifications
H; H04; H04M; H04M15/00; H04M15/38
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1673420A
Cited
US1800240A
Cited
US1962619A
Cited
US2486722A
Cited
US2385228A
Cited
US2426981A
Cited
US2586704A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-02-19 | 1960-08-20 | 1961-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-02-19 | 1964-08-20 | 1965-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-02-19 | 1968-08-20 | 1969-02-19 | $7700.00 | Window Closed / Lapsed |