看一下http://www.google.com/search?hl=zh-CN&inlang=zh-CN&ie=GB2312&newwindow=1&q=ADSL%C3%DC%C2%EB%D6%D5%BD%E1%D5%DF%D7%A2%B2%E1%B0%E6&lr=lang_zh-CN%7Clang_zh-TW