Patent US2904636A successfully refreshed from Google Patents.
US2904636A
Expired / Lapsed
US
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Telephone circuit using magnetic cores
Assignee: AT&T Inc
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Filing: 1955-12-22
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Granted: 1959-09-15
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Expires: 1975-12-22
Abstract
No abstract record available.
Inventors
- 👤 Mckim Burton
- 👤 Richard J Stapleton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:08
CPC Classifications
G; G11; G11C; G11C19/00; G11C19/02; G11C19/04; H; H03; H03K; H03K23/00; H03K23/76; H04; H04Q; H04Q3/00; H04Q3/42
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) | 1962-09-14 | 1963-03-16 | 1963-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-09-14 | 1967-03-16 | 1967-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-09-14 | 1971-03-16 | 1971-09-15 | $7700.00 | Window Closed / Lapsed |