US2535446A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carrier communication system
Assignee: AT&T Inc
•
Filing: 1948-06-16
•
Granted: 1950-12-26
•
Expires: 1968-06-16
Abstract
No abstract record available.
Inventors
- 👤 Mitchell Doren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 02:34
CPC Classifications
H; H04; H04M; H04M7/00; H04M7/16
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2202474A
Cited
US2294905A
Cited
US2440277A
Cited
US2421727A
Cited
US2440239A
Cited
US2430471A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-12-25 | 1954-06-26 | 1954-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-12-25 | 1958-06-26 | 1958-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-12-25 | 1962-06-26 | 1962-12-26 | $7700.00 | Window Closed / Lapsed |