US3120581A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic automatic telephone switching system
Assignee: AT&T Inc
•
Filing: 1956-11-19
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Granted: 1964-02-04
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Expires: 1976-11-19
Abstract
No abstract record available.
Inventors
- 👤 Chester E Brooks
- 👤 Kenneth W Pfleger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:35
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/42; H04Q3/54; H04Q3/545
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
94 words
IN A TELEPHONE SWITCHING SYSTEM, IN COMBINATION, A PLURALITY OF SUBSCRIBERS'' LINES, A SOURCE OF ELECTRICAL ENERGY FOR ENERGIZING SAID SUBSCRIBERS'' LINES, A PHOTOTRANSISTOR INDIVIDUAL TO EACH OF SAID SUBSCRIBERS'' LINES INTERCONNECTED WITH THE RESPECTIVE SUBSCRIBERS'' LINES AND SAID SOURCE OF ELECTRICAL ENERGY, A PAIR OF CATHODE RAY BEAM ELECTRON DISCHARGE TUBES EACH HAVING A PHOSPHOR AT ONE END THEREOF, MEANS FOR SUPPORTING SAID PHOTOTRANSISTORS BETWEEN SAID ENDS OF SAID TUBES, AND MEANS FOR SIMULTANEOUSLY DIRECTING THE BEAMS WITHIN SAID TUBES TO ENERGIZE A SMALL SECTION OF THE RESPECTIVE PHOSPHORS ADJACENT THE SAME PHOTOTRANSISTOR.
Claim 2
Dependent Claim
94 words
IN A TELEPHONE SWITCHING SYSTEM, IN COMBINATION, A PLURALITY OF SUBSCRIBERS'' LINES, A SOURCE OF ELECTRICAL ENERGY FOR ENERGIZING SAID SUBSCRIBERS'' LINES, A PHOTOTRANSISTOR INDIVIDUAL TO EACH OF SAID SUBSCRIBERS'' LINES INTERCONNECTED WITH THE RESPECTIVE SUBSCRIBERS'' LINES AND SAID SOURCE OF ELECTRICAL ENERGY, A PAIR OF CATHODE RAY BEAM ELECTRON DISCHARGE TUBES EACH HAVING A PHOSPHOR AT ONE END THEREOF, MEANS FOR SUPPORTING SAID PHOTOTRANSISTORS BETWEEN SAID ENDS OF SAID TUBES, AND MEANS FOR SIMULTANEOUSLY DIRECTING THE BEAMS WITHIN SAID TUBES TO ENERGIZE A SMALL SECTION OF THE RESPECTIVE PHOSPHORS ADJACENT THE SAME PHOTOTRANSISTOR.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1967-02-03 | 1967-08-05 | 1968-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-02-03 | 1971-08-05 | 1972-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-02-03 | 1975-08-05 | 1976-02-04 | $7700.00 | Window Closed / Lapsed |