US2553255A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone substation apparatus
Assignee: AT&T Inc
•
Filing: 1948-09-28
•
Granted: 1951-05-15
•
Expires: 1968-09-28
Abstract
No abstract record available.
Inventors
- 👤 John M Hayward
- 👤 Jr Charles A Johnson
- 👤 Wilson R Neisser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:16
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1122290A
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US1144399A
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US1774421A
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US1905276A
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US2066876A
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US2105749A
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FR834981A
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US2279713A
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US2233107A
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US2417420A
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US2344689A
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US2409588A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-05-14 | 1954-11-13 | 1955-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-05-14 | 1958-11-13 | 1959-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-05-14 | 1962-11-13 | 1963-05-15 | $7700.00 | Window Closed / Lapsed |