[电] voice-frequency multichannel te-legraphy
yīn pín duō lù diàn bào shù ㄧㄣ ㄆㄧㄣˊ ㄉㄨㄛ ㄌㄨˋ ㄉㄧㄢˋ ㄅㄠˋ ㄕㄨˋ