Patent US2674734A successfully refreshed from Google Patents.
US2674734A
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US
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Electronic ringing frequency generator
Assignee: Automatic Electric Laboratories Inc
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Filing: 1950-07-20
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Granted: 1954-04-06
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Expires: 1970-07-20
Abstract
No abstract record available.
Inventors
- 👤 Harold J Mccreary
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:27
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-04-05 | 1957-10-05 | 1958-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-04-05 | 1961-10-05 | 1962-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-04-05 | 1965-10-05 | 1966-04-06 | $7700.00 | Window Closed / Lapsed |