US2589800A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone signaling system
Assignee: AT&T Inc
•
Filing: 1950-05-19
•
Granted: 1952-03-18
•
Expires: 1970-05-19
Abstract
No abstract record available.
Inventors
- 👤 Jr Walter D Goodale
- 👤 William H Martin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:01
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02; H04M19/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US978695A
Cited
US1295454A
Cited
US1279882A
Cited
US1852045A
Cited
US2332448A
Cited
US2340798A
Cited
US2455286A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-03-18 | 1955-09-17 | 1956-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-03-18 | 1959-09-17 | 1960-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-03-18 | 1963-09-17 | 1964-03-18 | $7700.00 | Window Closed / Lapsed |