US2697141A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noise eliminating device for telephone transmitters
Assignee: AT&T Inc
•
Filing: 1952-04-28
•
Granted: 1954-12-14
•
Expires: 1972-04-28
Abstract
No abstract record available.
Inventors
- 👤 Luther A Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:57
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/22; H04R1/222
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-12-13 | 1958-06-14 | 1958-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-12-13 | 1962-06-14 | 1962-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-12-13 | 1966-06-14 | 1966-12-14 | $7700.00 | Window Closed / Lapsed |