Asynchronous Digital Subscriber Line

Asynchronous Digital Subscriber Line (ADSL), a form of DSL, is a high speed data communications technology enabling use of existing analog telephone lines for access to the Internet and other services.

Using bandwidth higher that that of voice signals on the telephone line, it is always on, requiring no dialing to initiate a connection. To optimize performance in typical applications, it is asymmetric: the received or downstream rate is higher than the transmitted or upstream rate. Data and voice communications occur simultaneously on the same telephone line. Downstream rates are as high as 6 mbps.

See also: DSL SDSL?