发明名称 Ringing controller
摘要 In a telecommunications system, a switching device selectively applies one of two different voltage supplies to a common node. A first of the voltage supplies is coupled to the common node by a first switch and a second of the voltage supplies is coupled to the common node by a second switch. The switching device includes the following elements. A difference detector detects a difference between the first and second voltage supplies. A control circuit selectively enables one of the first and second switches and disables the other of the first and second switches, for switching between the first and second voltage supplies in response to the difference detector. The control circuit performs the switching between the first and second voltage supplies when the detected difference falls below a predetermined threshold.
申请公布号 US7209554(B2) 申请公布日期 2007.04.24
申请号 US20020281406 申请日期 2002.10.24
申请人 CIENA CORPORATION 发明人 MCGINN S. DONALD
分类号 H04M1/00;H04M9/00;H04M19/02 主分类号 H04M1/00
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