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Patent US2572831A successfully refreshed from Google Patents.
US2572831A
Expired / Lapsed
US
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Communication system
Assignee: AT&T Inc
•
Filing: 1947-11-24
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Granted: 1951-10-30
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Expires: 1967-11-24
Abstract
No abstract record available.
Inventors
- 👤 Walter M Bacon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:03
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/54
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1343256A
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US2495682A
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US2269379A
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US2279295A
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US2392356A
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US2495683A
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US2400124A
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US2346173A
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US2361342A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-10-29 | 1955-04-30 | 1955-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-10-29 | 1959-04-30 | 1959-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-10-29 | 1963-04-30 | 1963-10-30 | $7700.00 | Window Closed / Lapsed |