Patent US1517553A successfully refreshed from Google Patents.
US2702831A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ringing control circuit for telephone systems
Assignee: Stromberg Carlson Corp
•
Filing: 1953-01-02
•
Granted: 1955-02-22
•
Expires: 1973-01-02
Abstract
No abstract record available.
Inventors
- 👤 Elliott George
- 👤 William W Pharis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:31
CPC Classifications
H; H04; H04Q; H04Q5/00; H04Q5/02
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2490054A
Cited
US2535675A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-02-21 | 1958-08-23 | 1959-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-02-21 | 1962-08-23 | 1963-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-02-21 | 1966-08-23 | 1967-02-22 | $7700.00 | Window Closed / Lapsed |