In communications, an equipment that compresses the outgoing speech volume range and expands the incoming speech volume range on along distance telephone circuit. Such equipment makes efficient use of voice telecommunication channels.

• 在通信技术中的一种设备,用于压缩出现语音信号的振幅范围和扩展入站语音信号的振幅范围,以便在长距离的话音线路上进行传输。这种设备可以更有效地利用音频电信信道。