Patent US2187784A successfully refreshed from Google Patents.
US2187784A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone system
Assignee: AT&T Inc
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Filing: 1938-06-17
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Granted: 1940-01-23
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Expires: 1958-06-17
Abstract
No abstract record available.
Inventors
- 👤 Ralph E Hersey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:50
CPC Classifications
H; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/20; H04Q1/22; H04Q1/24
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) | 1943-01-22 | 1943-07-24 | 1944-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-01-22 | 1947-07-24 | 1948-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-01-22 | 1951-07-24 | 1952-01-23 | $7700.00 | Window Closed / Lapsed |