Patent US3462557A successfully refreshed from Google Patents.
US3462557A
Expired / Lapsed
US
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Intra-concentrator call detecting circuit
Assignee: AT&T Inc
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Filing: 1965-12-27
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Granted: 1969-08-19
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Expires: 1985-12-27
Abstract
No abstract record available.
Inventors
- 👤 Chester E Brooks
- 👤 James L Henry
- 👤 Peter B Linhart
- 👤 Grace E Markthaler
- 👤 Donald R Massoni
- 👤 John A Meyerle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:23
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/0004
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-08-18 | 1973-02-17 | 1973-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-08-18 | 1977-02-17 | 1977-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-08-18 | 1981-02-17 | 1981-08-19 | $7700.00 | Window Closed / Lapsed |