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US2981806A
Expired / Lapsed
US
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Automatic service observer-recorder circuits
Assignee: AT&T Inc
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Filing: 1958-04-22
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Granted: 1961-04-25
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Expires: 1978-04-22
Abstract
No abstract record available.
Inventors
- 👤 Jack K Middaugh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:44
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/22; H04M3/36
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2623108A
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US2685683A
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US2865998A
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US2886642A
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US2848543A
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US2841657A
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US2812385A
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US2886643A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-04-24 | 1964-10-24 | 1965-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-04-24 | 1968-10-24 | 1969-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-04-24 | 1972-10-24 | 1973-04-25 | $7700.00 | Window Closed / Lapsed |