Patent US2901542A successfully refreshed from Google Patents.
US2901542A
Expired / Lapsed
US
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"wake up" or "morning call" system for automatically signaling private branch exchange extension stations
Assignee: AT&T Inc
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Filing: 1956-10-12
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Granted: 1959-08-25
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Expires: 1976-10-12
Abstract
No abstract record available.
Inventors
- 👤 Eugene W Henches
- 👤 Ivan R Sheldon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:40
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/42; H04M3/432
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1295096A
Cited
US1302767A
Cited
US2413825A
Cited
GB577258A
Cited
US2483214A
Cited
US2465826A
Cited
US2555714A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-08-24 | 1963-02-23 | 1963-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-08-24 | 1967-02-23 | 1967-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-08-24 | 1971-02-23 | 1971-08-25 | $7700.00 | Window Closed / Lapsed |