US1721567A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiplex radio transmitting system
Assignee: AT&T Inc
•
Filing: 1928-02-07
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Granted: 1929-07-23
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Expires: 1948-02-07
Abstract
No abstract record available.
Inventors
- 👤 De Loss K Martin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:54
CPC Classifications
H; H03; H03H; H03H11/00; H03H11/02; H03H11/34
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) | 1932-07-22 | 1933-01-21 | 1933-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1936-07-22 | 1937-01-21 | 1937-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1940-07-22 | 1941-01-21 | 1941-07-23 | $7700.00 | Window Closed / Lapsed |