US3466403A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone calling tone circuit
Assignee: Individual
•
Filing: 1965-10-13
•
Granted: 1969-09-09
•
Expires: 1985-10-13
Abstract
No abstract record available.
Inventors
- 👤 John Hayden Combridge
- 👤 John Douglas Collingwood
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:28
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02; H04M19/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2589800A
Cited
US3387097A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-09-08 | 1973-03-10 | 1973-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-09-08 | 1977-03-10 | 1977-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-09-08 | 1981-03-10 | 1981-09-09 | $7700.00 | Window Closed / Lapsed |