US2547020A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and means for the transmission of low-frequency calls intelecommunication systems by interrupting the carrier
Assignee: International Standard Electric Corp
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Filing: 1947-07-25
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Granted: 1951-04-03
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Expires: 1967-07-25
Abstract
No abstract record available.
Inventors
- 👤 Lalande Marc Andre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:51
CPC Classifications
H; H04; H04J; H04J1/00; H04J1/02; H04J1/14; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/14; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/44; H04Q1/442; H04Q1/4423
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1624506A
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US1862608A
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US2162268A
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US2244240A
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US2284085A
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US2299945A
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US2306687A
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US2319306A
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US2442238A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-04-02 | 1954-10-02 | 1955-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-04-02 | 1958-10-02 | 1959-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-04-02 | 1962-10-02 | 1963-04-03 | $7700.00 | Window Closed / Lapsed |