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Patent US1752303A successfully refreshed from Google Patents.
US1752303A
Expired / Lapsed
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Interference neutralizer for alternating-current telegraph systems
Assignee: AT&T Inc
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Filing: 1930-01-24
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Granted: 1930-04-01
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Expires: 1950-01-24
Abstract
No abstract record available.
Inventors
- 👤 Leo A Kelley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:52
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/08; H04L25/085
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1933-03-31 | 1933-09-30 | 1934-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1937-03-31 | 1937-09-30 | 1938-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1941-03-31 | 1941-09-30 | 1942-04-01 | $7700.00 | Window Closed / Lapsed |