扩展现有电话用户线传送容量的新技术章燕翼现代通信已经进入了光纤通信的时代，长途通信干线和市内中继线已开始使用光缆。现有的电话用户线所采用的对绞铜线始于１８８１年。对绞铜线属电气平衡的结构，它使线对与线对之间的干扰减到最小，有利于电话通信质量的提高，因... New Technology for Expanding Existing Telephony Subscriber Line Transmission Volumes Zhang Yan-yi Modern communications has entered the era of optical fiber communications. Long-distance communications trunks and municipal trunks have begun to use optical fiber cables. The twisted copper wire used in existing telephone subscriber lines began in 1881. The twisted copper wire is an electrical balance structure that minimizes the interference between the wire pair and the wire pair, which is advantageous for improving the quality of the telephone communication due to ...