Patent US1563326A successfully refreshed from Google Patents.
US1563326A
Expired / Lapsed
US
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Secret-communication system
Assignee: AT&T Inc
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Filing: 1921-11-08
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Granted: 1925-12-01
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Expires: 1941-11-08
Abstract
No abstract record available.
Inventors
- 👤 Bown Ralph
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:47
CPC Classifications
H; H04; H04K; H04K1/00; H04K1/04
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) | 1928-11-30 | 1929-06-01 | 1929-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1932-11-30 | 1933-06-01 | 1933-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1936-11-30 | 1937-06-01 | 1937-12-01 | $7700.00 | Window Closed / Lapsed |