ADSL方式接入。数字用户线系统（XDSL）是一种基于双绞线的有效宽带接入技术。ADSL非常适合于用户密度低居民区和地理上分散的小企业或部门。ADSL接入方案最大的优点在于不改造现有线路，而用较低的价格给用户提供了高速的上网方式。目前很多ISP已提供了ADSL接入方式，并且采用 ADSL way to access. Digital Subscriber Line System (XDSL) is an effective twisted pair based broadband access technology. ADSL is ideally suited for small businesses or departments with low user density in residential areas and geographically dispersed. The biggest advantage of ADSL access scheme is that it does not transform existing lines, but provides users with high-speed access to the Internet at a lower price. At present, many ISPs have provided ADSL access methods and adopted