US2501820A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Intercommunication system
Assignee: RCA Corp
•
Filing: 1948-04-29
•
Granted: 1950-03-28
•
Expires: 1968-04-29
Abstract
No abstract record available.
Inventors
- 👤 Winfield R Koch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:20
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/001; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/54
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1633100A
Cited
US1361488A
Cited
US1885010A
Cited
US1579256A
Cited
US1666738A
Cited
US1746808A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-03-27 | 1953-09-26 | 1954-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-03-27 | 1957-09-26 | 1958-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-03-27 | 1961-09-26 | 1962-03-28 | $7700.00 | Window Closed / Lapsed |