Patent US4670696A successfully refreshed from Google Patents.
US2432276A
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Frequency determining circuit for telephone ringing current and the like
Assignee: LEICH ELECTRIC CO
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Filing: 1944-07-24
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Granted: 1947-12-09
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Expires: 1964-07-24
Abstract
No abstract record available.
Inventors
- 👤 Hans P Boswau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:06
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/54; H02M7/58; H02M7/62; H04; H04M; H04M19/00; H04M19/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1307517A
Cited
US1292815A
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US1296269A
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US2035875A
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US2129747A
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US2258303A
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US2313527A
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US2298003A
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US2210211A
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US2265717A
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US2352299A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-12-08 | 1951-06-09 | 1951-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-12-08 | 1955-06-09 | 1955-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-12-08 | 1959-06-09 | 1959-12-09 | $7700.00 | Window Closed / Lapsed |