US3230315A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Two-wire switching system for fourwire circuits
Assignee: TDK Micronas GmbH
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Filing: 1962-06-04
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Granted: 1966-01-18
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Expires: 1982-06-04
Abstract
No abstract record available.
Inventors
- 👤 Robert V Judy
- 👤 Roger E Arseneau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:48
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/42; H04M3/56; H04M3/40
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
110 words
A TELEPHONE SYSTEM COMPRISING FOUR-WIRE SWITCHING MEANS FOR EXTENDING A PLUALITY OF FOUR-WIRE LINES TO A CONFERENCE CALL CIRCUIT, MEANS IN SAID CONFERENCE CALL CIRCUIT COMPRISING A PAIR OF OPPOSITELY POLED AMPLIFIERS ASSOCIATED WITH EACH OF SAID LINES FOR CONNECTING SAID FOURWIRE LINES TO TWO-WIRE TERMINALS, A FIRST OF SAID AMPLIFIERS HAVING A RELATIVELY HIGH OUTPUT IMPEDANCE, THE SECOND OF SAID AMPLIFIERS HAVING A RELATIVELY HIGH INPUT IMPEDANCE, LOW INPUT IMPEDANCE MEANS COUPLED TO SAID TWOWIRE TERMINALS FOR LINKING SAID FIRST AMPLIFIER OUTPUT TO SAID SECOND AMPLIFIER INPUT, AND MEANS INTERCONNECTING SAID AMPLIFIERS TO CONTROL THE VOLUME OF SAID SECOND AMPLIFIER AS A FUNCTION OF SIGNALS IN SAID FIRST AMPLIFIER.
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) | 1969-01-17 | 1969-07-19 | 1970-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-01-17 | 1973-07-19 | 1974-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-01-17 | 1977-07-19 | 1978-01-18 | $7700.00 | Window Closed / Lapsed |