1·Simple introduce the XDSL accessing network technology based on the copper thread, and has carried on the more detailed introduction to SDSL's technology.
对基于铜线的接入网技术XDSL做了简单的介绍，并对SDSL技术进行了较详细的介绍。
2·Very-high-speed digital subscriber line(VDSL) is the fastest access technology of the xDSL family.
甚高速数字用户线（VDSL）是数字用户线（DSL）家族中速率最高的接入方式。