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US2604544A
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Carrier telephone system with audio-frequency signaling
Assignee: W C DILLON AND CO Inc
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Filing: 1949-12-30
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Granted: 1952-07-22
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Expires: 1969-12-30
Abstract
No abstract record available.
Inventors
- 👤 William C Dillon
- 👤 Clarence H Kehm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:27
CPC Classifications
H; H04; H04Q; H04Q5/00; H04Q5/02; H04M; H04M9/00; H04M9/02; H04M9/022; H04M9/027
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1662966A
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US1821758A
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US1896487A
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US1975932A
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US2064907A
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US2044305A
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US2449391A
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US2510271A
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US2440239A
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US2518374A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-07-22 | 1956-01-21 | 1956-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-07-22 | 1960-01-21 | 1960-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-07-22 | 1964-01-21 | 1964-07-22 | $7700.00 | Window Closed / Lapsed |