US2237742A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone system
Assignee: AT&T Inc
•
Filing: 1939-11-28
•
Granted: 1941-04-08
•
Expires: 1959-11-28
Abstract
No abstract record available.
Inventors
- 👤 Alexis A Lundstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:37
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/42
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1944-04-07 | 1944-10-07 | 1945-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-04-07 | 1948-10-07 | 1949-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-04-07 | 1952-10-07 | 1953-04-08 | $7700.00 | Window Closed / Lapsed |