US3428753A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Long-distance telephone system
Assignee: Siemens AG
•
Filing: 1964-10-12
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Granted: 1969-02-18
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Expires: 1984-10-12
Abstract
No abstract record available.
Inventors
- 👤 Friedrich Pfleiderer
- 👤 Heinz Mertel
- 👤 Erik Hoffmann
- 👤 Ekkehard Seidel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:25
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/0016
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-02-18 | 1972-08-19 | 1973-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-02-18 | 1976-08-19 | 1977-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-02-18 | 1980-08-19 | 1981-02-18 | $7700.00 | Window Closed / Lapsed |