发明名称 |
Trunk interface circuitry for telephone systems |
摘要 |
This invention relates to improved trunk interface circuitry for telephone system common equipment, which is used to connect a local customer system to a central office of the telephone company. The improved trunk interface comprises an active two-terminal current sink for limiting the loop current in a non-linear manner, and means for monitoring the voltage across the trunk line which comprises a voltage-to-pulse width converter. The voltage-to-pulse width converter is designed to operate with a microprocessor which measures the time it takes to linearly discharge a capacitor which has been charged to the line voltage.
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申请公布号 |
US4894860(A) |
申请公布日期 |
1990.01.16 |
申请号 |
US19880203722 |
申请日期 |
1988.06.07 |
申请人 |
TIE/COMMUNICATIONS, INC. |
发明人 |
KORSKY, VINCENT V.;KRZYSZCZYK, RAJMUND;LIM, JIN T. |
分类号 |
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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