US2714632A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ringing generator and interrupter using electron tubes
Assignee: AT&T Inc
•
Filing: 1949-12-20
•
Granted: 1955-08-02
•
Expires: 1969-12-20
Abstract
No abstract record available.
Inventors
- 👤 Nathan I Hall
- 👤 Franklin A Korn
- 👤 Harold E Powell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:21
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02
Claims Analysis
Total Claims: 0
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-08-01 | 1959-01-31 | 1959-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-08-01 | 1963-01-31 | 1963-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-08-01 | 1967-01-31 | 1967-08-02 | $7700.00 | Window Closed / Lapsed |