US2571680A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulse code modulation system employing code substitution
Assignee: AT&T Inc
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Filing: 1949-02-11
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Granted: 1951-10-16
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Expires: 1969-02-11
Abstract
No abstract record available.
Inventors
- 👤 Robert L Carbrey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:56
CPC Classifications
H; H03; H03M; H03M5/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-10-15 | 1955-04-16 | 1955-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-10-15 | 1959-04-16 | 1959-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-10-15 | 1963-04-16 | 1963-10-16 | $7700.00 | Window Closed / Lapsed |