Patent US2438492A successfully refreshed from Google Patents.
US2438492A
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US
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Signaling system
Assignee: AT&T Inc
•
Filing: 1944-08-17
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Granted: 1948-03-30
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Expires: 1964-08-17
Abstract
No abstract record available.
Inventors
- 👤 Henry M Bascom
- 👤 Robert F Massonneau
- 👤 Jr Bernard Ostendorf
- 👤 Wilton T Rea
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:40
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/24; H03; H03K; H03K23/00; H03K23/82; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/44
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1882010A
Cited
US2248937A
Cited
US2096954A
Cited
US2192217A
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GB355705A
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US1930609A
Cited
GB411903A
Cited
US2225680A
Cited
GB485703A
Cited
US2241156A
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US2273193A
Cited
US2332300A
Cited
US2373134A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-03-30 | 1951-09-29 | 1952-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-03-30 | 1955-09-29 | 1956-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-03-30 | 1959-09-29 | 1960-03-30 | $7700.00 | Window Closed / Lapsed |