Patent US2723311A successfully refreshed from Google Patents.
US2723311A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Common control telephone systems
Assignee: AT&T Inc
•
Filing: 1953-03-05
•
Granted: 1955-11-08
•
Expires: 1973-03-05
Abstract
No abstract record available.
Inventors
- 👤 William A Malthaner
- 👤 Henry E Vaughan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:01
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/08; H04M3/12; H04M3/22; H04M3/36; H04Q; H04Q3/00; H04Q3/42; H04Q3/54; H04M2201/00; H04M2201/08; H04M2201/10; H04Q2213/00; H04Q2213/1302; H04Q2213/1304
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-11-07 | 1959-05-09 | 1959-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-11-07 | 1963-05-09 | 1963-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-11-07 | 1967-05-09 | 1967-11-08 | $7700.00 | Window Closed / Lapsed |