在所有这些xdsl技术当中，ADSL 是最具前景 及竞争力的一种，将在未来十几年甚至几十年内占主导地位。在系统中，常用的调制方式有QAM离散多音频DMT-Xdsl technology in which all of these, ADSL is the most prospects and a competitive edge, will in the next ten years or even decades dominated. In the system, are commonly

Discrete Multi Tone (DMT) is the modulation scheme used for Asymmetric Digital Subscriber Line (ADSL) systems and one of the modulation schemes used for Very high-speed Digital Subscriber Line (VDSL) systems.