发明名称 |
AC supervisory signal detector circuit |
摘要 |
An AC supervisory signal detector circuit for use in conjunction with a trunk circuit of a digital PABX telephone system interfacing with a central office providing for detection of relatively low frequency AC voltages which may be superimposed upon a DC bias voltage of either polarity. The circuit is equally responsive to various frequencies used in supervisory type signaling.
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申请公布号 |
US4133982(A) |
申请公布日期 |
1979.01.09 |
申请号 |
US19770864051 |
申请日期 |
1977.12.23 |
申请人 |
GTE AUTOMATIC ELECTRIC LABORATORIES INCORPORATED |
发明人 |
LEE, DAVID Q.;ROVNYAK, RICHARD M. |
分类号 |
H04M7/00;H04Q1/442;(IPC1-7):H04M7/00 |
主分类号 |
H04M7/00 |
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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