US3517133A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Four wire telephone system using phantom signaling circuit
Assignee: International Standard Electric Corp
•
Filing: 1966-07-20
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Granted: 1970-06-23
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Expires: 1986-07-20
Abstract
No abstract record available.
Inventors
- 👤 Ronald George Knight
- 👤 John Anthony Weeks Butcher
- 👤 Geoffrey George Pullum
- 👤 Michael John Willson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:53
CPC Classifications
H; H04; H04M; H04M1/00; H04Q; H04Q3/00
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) | 1973-06-22 | 1973-12-22 | 1974-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-06-22 | 1977-12-22 | 1978-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-06-22 | 1981-12-22 | 1982-06-23 | $7700.00 | Window Closed / Lapsed |