Patent US3518454A successfully refreshed from Google Patents.
US3518454A
Expired / Lapsed
US
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Bidirectional transmission circuit
Assignee: AT&T Inc
•
Filing: 1967-10-20
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Granted: 1970-06-30
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Expires: 1987-10-20
Abstract
No abstract record available.
Inventors
- 👤 Joseph C French
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:01
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/687; H03K17/6871; H03F; H03F3/00; H03F3/50; H03F3/505; H03K3/00; H03K3/02; H03K3/353; H03K3/355
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3436672A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-06-29 | 1973-12-29 | 1974-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-06-29 | 1977-12-29 | 1978-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-06-29 | 1981-12-29 | 1982-06-30 | $7700.00 | Window Closed / Lapsed |