Patent US2492381A successfully refreshed from Google Patents.
US2492381A
Expired / Lapsed
US
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Device for timing telephone calls
Assignee: AT&T Inc
•
Filing: 1945-04-21
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Granted: 1949-12-27
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Expires: 1965-04-21
Abstract
No abstract record available.
Inventors
- 👤 Sanford F Dunning
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:42
CPC Classifications
H; H04; H04M; H04M15/00; H04M15/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1305981A
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US965453A
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US1647990A
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US1654923A
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US1726982A
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US1723153A
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US1853077A
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US1897533A
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US2196173A
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US2112375A
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US2428376A
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US2400085A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1952-12-26 | 1953-06-27 | 1953-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1956-12-26 | 1957-06-27 | 1957-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1960-12-26 | 1961-06-27 | 1961-12-27 | $7700.00 | Window Closed / Lapsed |