Asymmetric digital subscriber line is a type of digital subscriber line technology, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. Wikipedia

Internet connectivity Wikipedia Disambiguation

A form of DSL, a data communications technology that enables fast data transmission over copper telephone lines. It does this by utilizing frequencies higher than normal human hearing, that are not used by a voice telephone call. Contrary to other forms of DSL the volume of data flow is greater in one direction than the other, i.e. it is asymmetric. OmegaWiki