ADSL stands for A symmetric Digital Subscriber Line. It is a technology that allows data to be sent at high speeds across copper phone lines rather than conventional voice-band modems.ADSL2+ provides double the downstream rate compared to ADSL, from 12Mbps to 24Mbps. Data speed is dependent on the distance between the user's modem to the DSLAM (Digital Subscriber LineAccess Multiplexer), usually located at the local telecom exchange. VDSL stands for Very-high-bit-rate Digital Subscriber Line, which provides a faster data transmission than ADSL. VDSL is able to support applications like HDTV and VOIP (Voice over IP), and able to downstream data up to 100Mbps (or 300Mbps using VDSL VPlus).