US2668931A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic register for telephone switching systems
Assignee: AT&T Inc
•
Filing: 1949-12-20
•
Granted: 1954-02-09
•
Expires: 1969-12-20
Abstract
No abstract record available.
Inventors
- 👤 Nathan I Hall
- 👤 Hecht George
- 👤 Charles D Koechling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:24
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/42
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1498544A
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US2404918A
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US2462613A
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US2417831A
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US2428089A
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US2411441A
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US2438492A
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US2487781A
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US2452051A
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US2422523A
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US2515448A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-02-08 | 1957-08-10 | 1958-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-02-08 | 1961-08-10 | 1962-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-02-08 | 1965-08-10 | 1966-02-09 | $7700.00 | Window Closed / Lapsed |