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US3433902A
Expired / Lapsed
US
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Speech immunity voice frequency signalling systems
Assignee: International Standard Electric Corp
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Filing: 1966-10-31
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Granted: 1969-03-18
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Expires: 1986-10-31
Abstract
No abstract record available.
Inventors
- 👤 John Anthony Weeks Butcher
- 👤 Geoffrey George Pullum
- 👤 Michael John Willson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:46
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/26; H04M1/30; H04M1/50
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3270144A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-03-17 | 1972-09-16 | 1973-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-03-17 | 1976-09-16 | 1977-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-03-17 | 1980-09-16 | 1981-03-18 | $7700.00 | Window Closed / Lapsed |