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US3428751A
Expired / Lapsed
US
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Coin telephone antifraud circuit
Assignee: AT&T Inc
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Filing: 1966-01-28
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Granted: 1969-02-18
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Expires: 1986-01-28
Abstract
No abstract record available.
Inventors
- 👤 John E Edington
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:13
CPC Classifications
H; H04; H04M; H04M17/00; H04M17/02; H04M17/023
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3069502A
Cited
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 |