Patent US2506429A successfully refreshed from Google Patents.
US2506429A
Expired / Lapsed
US
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Selective signaling system
Assignee: AT&T Inc
•
Filing: 1946-05-31
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Granted: 1950-05-02
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Expires: 1966-05-31
Abstract
No abstract record available.
Inventors
- 👤 John M Melick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 08:02
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/42; H04M; H04M1/00; H04M1/26; H04M1/515
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1672005A
Cited
US2401729A
Cited
US2367522A
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US2400148A
Cited
US2381499A
Cited
US2393377A
Cited
US2411375A
Cited
US2396134A
Cited
US2411191A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-05-01 | 1953-10-31 | 1954-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-05-01 | 1957-10-31 | 1958-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-05-01 | 1961-10-31 | 1962-05-02 | $7700.00 | Window Closed / Lapsed |