Patent US3056931A successfully refreshed from Google Patents.
US3056931A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transistorized generator of telephone ringing current
Assignee: TDK Micronas GmbH
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Filing: 1958-05-07
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Granted: 1962-10-02
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Expires: 1978-05-07
Abstract
No abstract record available.
Inventors
- 👤 Leonard A Bloomquist
- 👤 Edward N Marsh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:07
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1965-10-01 | 1966-04-02 | 1966-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1969-10-01 | 1970-04-02 | 1970-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1973-10-01 | 1974-04-02 | 1974-10-02 | $7700.00 | Window Closed / Lapsed |