Patent US2541174A successfully refreshed from Google Patents.
Patent US2704787A successfully refreshed from Google Patents.
US2704787A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone trunk supervisory circuit
Assignee: Stromberg Carlson Corp
•
Filing: 1949-12-01
•
Granted: 1955-03-22
•
Expires: 1969-12-01
Abstract
No abstract record available.
Inventors
- 👤 William W Pharis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:34
CPC Classifications
H; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/32
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US1039988A
Cited
US2140601A
Cited
US2168198A
Cited
US2236276A
Cited
US2405597A
Cited
US2502687A
Cited
GB588402A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-03-21 | 1958-09-20 | 1959-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-03-21 | 1962-09-20 | 1963-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-03-21 | 1966-09-20 | 1967-03-22 | $7700.00 | Window Closed / Lapsed |