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US2993094A
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Frequency selective signaling system
Assignee: AT&T Inc
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Filing: 1958-10-10
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Granted: 1961-07-18
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Expires: 1978-10-10
Abstract
No abstract record available.
Inventors
- 👤 Danielsen Daniel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:33
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/42; H04Q3/52; H04Q3/521
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2769865A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-07-17 | 1965-01-16 | 1965-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-07-17 | 1969-01-16 | 1969-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-07-17 | 1973-01-16 | 1973-07-18 | $7700.00 | Window Closed / Lapsed |