telephone plant

XDSL have been considered the one of the technologies which have the good fortune and feasibility in recent years. xDSL systems are built upon the existing twisted-pair telephone subscriber loop plant and can provide different bandwidth by different modulation technologies, so different transmission rates are fulfilled.

xDSL技术被看作近年来最具发展前途和可行性的主流技术之一，xDSL是以现有的入户铜绞线为介质基础，通过不同的调制方式提供不同的带宽，从而实现不同速度的网络用户接入技术。

The centrol control room of sewage plant adopted telephone line as transmission medium between the control room and every supervisory control station; we can collect and deal data and control equipment in the station at the centrol room.

各监控站和污水处理厂的中控室之间采用电话线作为传输介质，通过调制解调器解析数据，在中控室可以采集处理各监控站的数据并控制现场设备。