US2594389A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Double-lockout interconnecting system
Assignee: AT&T Inc
•
Filing: 1948-08-04
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Granted: 1952-04-29
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Expires: 1968-08-04
Abstract
No abstract record available.
Inventors
- 👤 Bruce Edmond
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:35
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/0004
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-04-29 | 1955-10-29 | 1956-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-04-29 | 1959-10-29 | 1960-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-04-29 | 1963-10-29 | 1964-04-29 | $7700.00 | Window Closed / Lapsed |