US1688451A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone signaling system
Assignee: AT&T Inc
•
Filing: 1926-05-19
•
Granted: 1928-10-23
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Expires: 1946-05-19
Abstract
No abstract record available.
Inventors
- 👤 Charles S Demarest
- 👤 Owen H Loynes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:01
CPC Classifications
H; H04; H04M; H04M11/00
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) | 1931-10-23 | 1932-04-23 | 1932-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1935-10-23 | 1936-04-23 | 1936-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1939-10-23 | 1940-04-23 | 1940-10-23 | $7700.00 | Window Closed / Lapsed |