US2866005A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Make-busy circuit for trunks in unattended dial office
Assignee: AT&T Inc
•
Filing: 1955-04-29
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Granted: 1958-12-23
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Expires: 1975-04-29
Abstract
No abstract record available.
Inventors
- 👤 Arthur T Kupferle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:46
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/58
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2142653A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-12-22 | 1962-06-23 | 1962-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-12-22 | 1966-06-23 | 1966-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-12-22 | 1970-06-23 | 1970-12-23 | $7700.00 | Window Closed / Lapsed |