US3350508A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Immediate ringing circuit for telephone systems
Assignee: AT&T Inc
•
Filing: 1964-12-10
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Granted: 1967-10-31
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Expires: 1984-12-10
Abstract
No abstract record available.
Inventors
- 👤 Richard M Swanson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:01
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/0004
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
114 words
IN A TELEPHONE SYSTEM, A PLURALITY OF TELEPHONE LINES, A PLURALITY OF TRUNK MEANS SEIZABLE FOR CONNECTING INCOMING CALLS TO SAID LINES, RINGING MEANS FOR GENERATING A PLURALITY OF PHASE-DISPLACED RINGING SIGNALS, A PLURALITY OF RINGING SELECTION MEANS EACH COMPRISING CROSSBAR SWITCHING MEANS INCLUDING A PLURALITY OF LEVELS, PARTICUALR LEVELS OF SAID CROSSBAR SWITCHING MEANS EACH CORRESPONDING TO ONE OF SAID SIGNALS, SAID RINGING SELECTION MEANS COUPLING SAID RINGING MEANS AND SAID TRUNK MEANS, MARKER MEANS FOR ENERGIZING SAID RINGING SELECTION MEANS AND SYNCHRONIZING MEANS RESPONSIVE TO SAID RINGING MEANS FOR CONTROLLING SAID MARKER MEANS TO ENERGIZE THE ONE OF SAID RINGING SELECTION MEANS LEVELS COUPLED TO THE INSTANTANEOUSLY ACTIVE ONE OF SAID SIGNALS.
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) | 1970-10-30 | 1971-05-01 | 1971-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-10-30 | 1975-05-01 | 1975-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-10-30 | 1979-05-01 | 1979-10-31 | $7700.00 | Window Closed / Lapsed |