A telecom circuit composed of two pairs of wires or channels that can be used for coord circuits or commentary circuits. 一条包含两组电线或频道的线路,是协调通话和评论声传送的线路。
A telecom circuit composed of two pairs of wires or channels that can be used for coord circuits or commentary circuits. 一条包含两组电线或频道的线路,是协调通话和评论声传送的线路。