Patent US2818558A successfully refreshed from Google Patents.
US2818558A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Key pulsing circuit
Assignee: AT&T Inc
•
Filing: 1954-06-17
•
Granted: 1957-12-31
•
Expires: 1974-06-17
Abstract
No abstract record available.
Inventors
- 👤 Henry H Abbott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:11
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/02; H; H04; H04M; H04M1/00; H04M1/26; H04M1/30; H04M1/31; H04M1/312
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) | 1960-12-30 | 1961-07-01 | 1961-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-12-30 | 1965-07-01 | 1965-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-12-30 | 1969-07-01 | 1969-12-31 | $7700.00 | Window Closed / Lapsed |