US2499000A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency modulation system for locating impedance irregularities
Assignee: AT&T Inc
•
Filing: 1946-10-16
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Granted: 1950-02-28
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Expires: 1966-10-16
Abstract
No abstract record available.
Inventors
- 👤 Donald A Quarles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:53
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/28; G01R27/32; G01R31/00; G01R31/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2258677A
Cited
US2143094A
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US2203750A
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US2253975A
Cited
US2214130A
Cited
US2268587A
Cited
US2315383A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-02-27 | 1953-08-29 | 1954-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-02-27 | 1957-08-29 | 1958-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-02-27 | 1961-08-29 | 1962-02-28 | $7700.00 | Window Closed / Lapsed |