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US2718557A
Expired / Lapsed
US
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Auxiliary-service telephone system
Assignee: TDK Micronas GmbH
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Filing: 1951-11-01
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Granted: 1955-09-20
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Expires: 1971-11-01
Abstract
No abstract record available.
Inventors
- 👤 Jr Richard P Boyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 04:38
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/08; H04M3/12; H04Q; H04Q3/00; H04Q3/0004
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) | 1958-09-19 | 1959-03-21 | 1959-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-09-19 | 1963-03-21 | 1963-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-09-19 | 1967-03-21 | 1967-09-20 | $7700.00 | Window Closed / Lapsed |