Patent US3521068A successfully refreshed from Google Patents.
US3521068A
Expired / Lapsed
US
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Optical time division multiplex communication system
Assignee: International Business Machines Corp
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Filing: 1967-06-15
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Granted: 1970-07-21
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Expires: 1987-06-15
Abstract
No abstract record available.
Inventors
- 👤 John A Armstrong
- 👤 William V Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:56
CPC Classifications
H; H04; H04J; H04J14/00; H04J14/08; G; G02; G02F; G02F2/00
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) | 1973-07-20 | 1974-01-19 | 1974-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-20 | 1978-01-19 | 1978-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-20 | 1982-01-19 | 1982-07-21 | $7700.00 | Window Closed / Lapsed |