发明名称 |
Telephone subscriber circuit with galvanic isolation |
摘要 |
A telephone subscriber circuit is coupled via a single galvanic isolation element to provide, from a subscriber apparatus unconnected to the telephone line, on- and off-hook signals to the telephone line and to control transfer of telephonic signals between the subscriber apparatus and the telephone line. The galvanic isolation element is a photocoupler. The subscriber circuit includes a speech circuit coupled to the line through a diode bridge circuit and an electronic switch is connected between the speech circuit and the diode bridge circuit. An input terminal of the speech circuit and a control terminal of the electronic switch are each connected through a voltage-generating circuit and level-translating circuit to an output terminal of the galvanic isolation element.
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申请公布号 |
US5692041(A) |
申请公布日期 |
1997.11.25 |
申请号 |
US19940330540 |
申请日期 |
1994.10.27 |
申请人 |
SGS-THOMSON MICROELECTRONICS S.R.L. |
发明人 |
TORAZZINA, ALDO |
分类号 |
H04M1/00;H04M1/654;H04M1/738;H04M11/00;(IPC1-7):H04M1/00 |
主分类号 |
H04M1/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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