[通信]?话音级信道

... voice-frequency 话音频率 voice-grade channel 话音级信道 voice-grade line 音频（通信）线路 ...

?话音级通道

... voice-frequency facility terminal(VFFT) 音频设施终端机 voice-grade channel 话音级通道 voice-grade lines 话音级线路 ...

?音频频道

... voice control 声控 voice-grade channel 音频频道 voice keying 语音键控 ...

?音频道

... 视平线 visual horizon 音频道 voice-grade channel 声音操作装置 voice-operated device ...