US1592940A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Secret signaling
Assignee: AT&T Inc
•
Filing: 1920-09-09
•
Granted: 1926-07-20
•
Expires: 1940-09-09
Abstract
No abstract record available.
Inventors
- 👤 Burton W Kendall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 19:26
CPC Classifications
H; H04; H04K; H04K1/00; H04K1/003
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) | 1929-07-19 | 1930-01-18 | 1930-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1933-07-19 | 1934-01-18 | 1934-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1937-07-19 | 1938-01-18 | 1938-07-20 | $7700.00 | Window Closed / Lapsed |