短語詞組短語circuit t switching 線路交換;通道轉換Circuit -switching vs packet-switching 電路交換與包交換vacuum circuit breaker switching 真空斷路器操作end -to- blocking circuit-switching 耑分區(qū)段電路開關circuit switching system 數據電路交換機;廻路交換方式FCS Fast Circuit Switching 快速線路切換 返回 circuit switching