US3542966A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Private automatic branch exchanges with callback traffic
Assignee: International Standard Electric Corp
•
Filing: 1967-04-14
•
Granted: 1970-11-24
•
Expires: 1987-04-14
Abstract
No abstract record available.
Inventors
- 👤 Heinz Schluter
- 👤 Hans Dieter Siebel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:51
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/42; H04M3/58
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3115552A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-11-23 | 1974-05-25 | 1974-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-11-23 | 1978-05-25 | 1978-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-11-23 | 1982-05-25 | 1982-11-24 | $7700.00 | Window Closed / Lapsed |