Patent US2855575A successfully refreshed from Google Patents.
US2855575A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Negative impedance amplifier with separate input and output particularly for telephone systems
Assignee: TELEFONICA INTERREGIONALE PIEM
•
Filing: 1956-07-30
•
Granted: 1958-10-07
•
Expires: 1976-07-30
Abstract
No abstract record available.
Inventors
- 👤 Tamburelli Giovanni
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:45
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/16
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) | 1961-10-06 | 1962-04-07 | 1962-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-10-06 | 1966-04-07 | 1966-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-10-06 | 1970-04-07 | 1970-10-07 | $7700.00 | Window Closed / Lapsed |