Patent US2980794A successfully refreshed from Google Patents.
US2980794A
Expired / Lapsed
US
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Automatic tone decoder
Assignee: Fairchild Semiconductor Corp
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Filing: 1957-06-13
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Granted: 1961-04-18
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Expires: 1977-06-13
Abstract
No abstract record available.
Inventors
- 👤 Hargreaves William Vernon
- 👤 Durgin Louis Austin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:47
CPC Classifications
H; H04; H04W; H04W88/00; H04W88/02; H04W88/022; H04W88/025; H04W88/027
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2524782A
Cited
US2579470A
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US2546987A
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US2457149A
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US2679000A
Cited
GB720699A
Cited
US2724049A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-04-17 | 1964-10-17 | 1965-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-04-17 | 1968-10-17 | 1969-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-04-17 | 1972-10-17 | 1973-04-18 | $7700.00 | Window Closed / Lapsed |