US2706223A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polytonic high speed calling signal generator
Assignee: AT&T Inc
•
Filing: 1953-05-27
•
Granted: 1955-04-12
•
Expires: 1973-05-27
Abstract
No abstract record available.
Inventors
- 👤 Clarence A Lovell
- 👤 Orlando J Murphy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:54
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2228113A
Cited
US2594300A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-04-11 | 1958-10-11 | 1959-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-04-11 | 1962-10-11 | 1963-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-04-11 | 1966-10-11 | 1967-04-12 | $7700.00 | Window Closed / Lapsed |