voice-frequency telegraph system [通信] 音频电报系统 ; 音频设施终端机

voice-frequency telegraph terminal 音频电报终端机

frequency shift voice frequency telegraph 移频音频电报

frequency modulated voice frequency telegraph 调频音频电报

shift voice frequency telegraph 移频音频电报

modulated voice frequency telegraph 调频音频电报

speech plus voice frequency telegraph 语音加话频电报

voice-frequency telegraph [通信] 音频电报

voice frequency telegraph bearer circuit 音频电报承载电路