DSL stands for Digital Subscriber Line. There are many types of DSL, but they are all just different ways of accomplishing the same thing. DSL uses the telephone company's existing copper wire to make very High-speed data links available.

Standard telephone service - commonly known as POTS or Plain Old Telephone Service - does not make use of the entire bandwidth range available on a copper telephone wire. The signal uses only the lower 4Khz, limiting the total possible bandwidth to 56k (without compression). DSL is able to operate at faster speeds by using much higher frequencies for communication - up to 1Mhz.

Previously, it was not possible to communicate at such high frequencies over the existing copper because of interference with regular telephone calls. New advances in digital signal processing have eliminated the problems that used to cause interference. In the next several years, DSL will be the fastest growing new technology made available to businesses. Its speed and reliability are among the two major factors that have created demand for DSL service.

DSL requires installation of two pieces of equipment -- one on each end of the telephone line. A typical configuration is for the service provider to place a DSLAM (DSL Access Multiplexer) in the telephone company's central office, and a DSL router at the user's end. The DSLAM concentrates the information from many DSL lines into a data network -- usually ATM or frame relay, and routes the incoming information to the end user.