[電學] 直流脈沖表轉換信號序列 dial train: 撥號音中繼線trains interval between dial pulses: 撥號盤脈沖串間隙dc switching point: 直流轉換點switching dc voltage: 開關直流電壓automatic dial switching network: 自動拔號交換網絡下載手機詞典可隨時隨地查詞查翻譯