Patent US1161932A successfully refreshed from Google Patents.
US2820103A
Expired / Lapsed
US
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Subscriber line concentrating system
Assignee: AT&T Inc
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Filing: 1954-09-30
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Granted: 1958-01-14
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Expires: 1974-09-30
Abstract
No abstract record available.
Inventors
- 👤 Henry H Abbott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:00
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/58
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2345628A
Cited
US2688662A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-01-13 | 1961-07-15 | 1962-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-01-13 | 1965-07-15 | 1966-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-01-13 | 1969-07-15 | 1970-01-14 | $7700.00 | Window Closed / Lapsed |