US2470145A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multifrequency signaling system
Assignee: AT&T Inc
•
Filing: 1947-09-25
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Granted: 1949-05-17
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Expires: 1967-09-25
Abstract
No abstract record available.
Inventors
- 👤 Clos Charles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:01
CPC Classifications
H; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/44; H04Q1/444; H04Q1/45; H04Q1/453
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2024012A
Cited
US1859885A
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US2192242A
Cited
US1834649A
Cited
US2075228A
Cited
US2206538A
Cited
US2332912A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1952-05-16 | 1952-11-15 | 1953-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1956-05-16 | 1956-11-15 | 1957-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1960-05-16 | 1960-11-15 | 1961-05-17 | $7700.00 | Window Closed / Lapsed |