DMT full-rate ADSL, expands the useable bandwidth of existing copper telephone lines, delivering high-speed data communications at rates up to 8 Mbps on the downstream, 864 Kbps on the upstream.是什么意思_DMT full-rate ADSL, expands the useable bandwidth of existing copper telephone lines, delivering high-speed data communications at rates up to 8 Mbps on the downstream, 864 Kbps on the upstream.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句