US2564441A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone system requiring different types of pulses
Assignee: AT&T Inc
•
Filing: 1949-12-29
•
Granted: 1951-08-14
•
Expires: 1969-12-29
Abstract
No abstract record available.
Inventors
- 👤 Mckim Burton
- 👤 Walter B Strickler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:25
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/0004
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1724142A
Cited
US2467490A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-08-13 | 1955-02-12 | 1955-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-08-13 | 1959-02-12 | 1959-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-08-13 | 1963-02-12 | 1963-08-14 | $7700.00 | Window Closed / Lapsed |