Patent US2520007A successfully refreshed from Google Patents.
US2520007A
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US
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Testing circuit for carrier communication system with automatic reset timer
Assignee: AT&T Inc
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Filing: 1947-11-21
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Granted: 1950-08-22
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Expires: 1967-11-21
Abstract
No abstract record available.
Inventors
- 👤 Hochgraf Lester
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:49
CPC Classifications
H; H04; H04J; H04J1/00; H04J1/02; H04J1/16
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) | 1953-08-21 | 1954-02-20 | 1954-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-08-21 | 1958-02-20 | 1958-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-08-21 | 1962-02-20 | 1962-08-22 | $7700.00 | Window Closed / Lapsed |