Patent US3205307A successfully refreshed from Google Patents.
US3205307A
Expired / Lapsed
US
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Circuit for intercommunication systems
Assignee: Individual
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Filing: 1961-10-19
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Granted: 1965-09-07
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Expires: 1981-10-19
Abstract
No abstract record available.
Inventors
- 👤 Schmitthenner Fred
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:27
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/001
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
79 words
AN ELECTRICAL INTERCOMMUNICATION SYSTEM COMPRISING: (A) AT LEAST THREE INDEPENDENT STATIONS EACH HAVING AN ACOUSTIC TRANSDUCER ADAPTED TO SERVE BOTH AS A MICROPHONE AND AS A SPEAKER, (B) A POWER SOURCE AND AN AMPLIFIER COMMON TO A PLURALITY OF SAID STATIONS, SAID AMPLIFIER HAVING A NORMALLY DISCONNECTED INPUT AND A NORMALLY DISCONNECTED OUTPUT, SAID POWER SOURCE PROVIDING DIRECT CURRENT, (C) A SWITCHING DEVICE, (D) FIRST MANUAL STATION SELECTOR MEANS FOR SELECTIVELY MANUALLY CONNECTING THE TRANSDUCER AT ONE OF SAID
Claim 2
Dependent Claim
79 words
AN ELECTRICAL INTERCOMMUNICATION SYSTEM COMPRISING: (A) AT LEAST THREE INDEPENDENT STATIONS EACH HAVING AN ACOUSTIC TRANSDUCER ADAPTED TO SERVE BOTH AS A MICROPHONE AND AS A SPEAKER, (B) A POWER SOURCE AND AN AMPLIFIER COMMON TO A PLURALITY OF SAID STATIONS, SAID AMPLIFIER HAVING A NORMALLY DISCONNECTED INPUT AND A NORMALLY DISCONNECTED OUTPUT, SAID POWER SOURCE PROVIDING DIRECT CURRENT, (C) A SWITCHING DEVICE, (D) FIRST MANUAL STATION SELECTOR MEANS FOR SELECTIVELY MANUALLY CONNECTING THE TRANSDUCER AT ONE OF SAID
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) | 1968-09-06 | 1969-03-08 | 1969-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-09-06 | 1973-03-08 | 1973-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-09-06 | 1977-03-08 | 1977-09-07 | $7700.00 | Window Closed / Lapsed |