US2591579A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permanent-signal indicating system
Assignee: AT&T Inc
•
Filing: 1948-10-29
•
Granted: 1952-04-01
•
Expires: 1968-10-29
Abstract
No abstract record available.
Inventors
- 👤 Michal Joseph
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:36
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/08; H04M3/14
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1655602A
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US1569677A
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US1569678A
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US1667015A
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US2143971A
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US2183656A
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US2183649A
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US2258980A
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US2372022A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-04-01 | 1955-10-01 | 1956-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-04-01 | 1959-10-01 | 1960-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-04-01 | 1963-10-01 | 1964-04-01 | $7700.00 | Window Closed / Lapsed |