US2921986A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Crossbar relay private branch exchange telephone system
Assignee: LEICH ELECTRIC CO
•
Filing: 1957-07-15
•
Granted: 1960-01-19
•
Expires: 1977-07-15
Abstract
No abstract record available.
Inventors
- 👤 Hans P Boswan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:40
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/0004
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2764634A
Cited
US2722568A
Cited
US2724020A
Cited
US2767248A
Cited
US2730568A
Cited
US2740003A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-01-18 | 1963-07-20 | 1964-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-01-18 | 1967-07-20 | 1968-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-01-18 | 1971-07-20 | 1972-01-19 | $7700.00 | Window Closed / Lapsed |