US2566840A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switch for telephone substation sets
Assignee: AT&T Inc
•
Filing: 1948-09-16
•
Granted: 1951-09-04
•
Expires: 1968-09-16
Abstract
No abstract record available.
Inventors
- 👤 Charles L Krumreich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:00
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/02; H04M1/04; H04M1/06; H04M1/08
Claims Analysis
Total Claims: 0
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US2452568A
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US2461360A
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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) | 1954-09-03 | 1955-03-05 | 1955-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-09-03 | 1959-03-05 | 1959-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-09-03 | 1963-03-05 | 1963-09-04 | $7700.00 | Window Closed / Lapsed |