The DSL or Digital Subscriber Loop Technology is the most efficient and cost-effective access solution of today. It uses the existing ubiquitous copper wire connecting most homes and businesses today to deliver high-speed data. It does so by dividing an existing telephone line's frequency into two portions: one for voice, and the other for data. With a single telephone line there is no interference between data transmission and voice, (i.e. a user can use the telephone and work on the Internet simultaneously). Since this connection is not dependent on a dial-up connection, it is "always on". Thus the subscriber never encounters disconnects or busy signals. An ASDL line consists of three information channels: a high-speed downstream channel, a medium-speed duplex channel, and a basic telephone service channel.
A line that delivers a much higher bandwidth than HDSL to a site than from it. Typically it will provide 6-10 Mbps to a site and 224-640 Kbps from it, depending on the distance from the central office. See high-bit-rate digital subscriber line.