US1557562A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency selective device
Assignee: AT&T Inc
•
Filing: 1919-10-16
•
Granted: 1925-10-20
•
Expires: 1939-10-16
Abstract
No abstract record available.
Inventors
- 👤 Crisson George
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:59
CPC Classifications
H; H03; H03H; H03H11/00; H03H11/02; H03H11/04
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) | 1928-10-19 | 1929-04-20 | 1929-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1932-10-19 | 1933-04-20 | 1933-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1936-10-19 | 1937-04-20 | 1937-10-20 | $7700.00 | Window Closed / Lapsed |