A high-speed connection to the Internet, can provide from six to 30 times the speed of 56k modem technology without needing very expensive equipment on the end-user side. Furthermore, DSL uses existing land lines in a userÂ’s home, allowing users to talk on the telephone line while connected to the Internet. As with cable modem technology, service providers have to upgrade their telephony networks to provide this service. In addition, the distance between the userÂ’s endpoint and the telephone exchange must not be longer than a few miles. For this reason, rural areas will continue to be underserved by high-speed Internet connections through DSL. Because DSL uses ATM, a layer-2 cell-switching fabric, it is vulnerable to crack attacks.

See Also: Asynchronous Transfer Mode (ATM) and the ATM Forum; Internet; Modem.