US3521005A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multifrequency signal generator
Assignee: AT&T Inc
•
Filing: 1966-09-01
•
Granted: 1970-07-21
•
Expires: 1986-09-01
Abstract
No abstract record available.
Inventors
- 👤 Robert J Dow
- 👤 Ralph W Wyndrum Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:14
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/26; H04M1/30; H04M1/50
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2778940A
Cited
US3184554A
Cited
US3212032A
Cited
US3072868A
Cited
US3242442A
Cited
US3223941A
Cited
US3361991A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-07-20 | 1974-01-19 | 1974-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-20 | 1978-01-19 | 1978-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-20 | 1982-01-19 | 1982-07-21 | $7700.00 | Window Closed / Lapsed |