DSL Access

DSL or xDSL, is a family of technologies that provide digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop, although in recent years, many have adopted digital subscriber line as a more marketing-friendly term for the most popular version of consumer-ready DSL, ADSL.

Typically, the download speed of consumer DSL services ranges from 256 kilobits per second (kbit/s) to 24,000 kbit/s, depending on DSL technology, line conditions and service level implemented. Typically, upload speed is lower than download speed for Asymmetric Digital Subscriber Line (ADSL) and equal to download speed for Symmetric Digital Subscriber Line (SDSL).

DSL connections work by dividing the frequencies used in a single phone line into two primary ‘bands’. The ISP data is carried over the high frequency band (25Khz and above) whereas the voice is carried over the lower frequency band (4Khz and below). The user typically installs a DSL filter on each phone. This filters out the high frequencies from the phone, so that the phone only sends or receives the lower frequencies (the human voice), creating two independent ‘bands’. Thus the DSL modem and the phone can simultaneously use the same phone line without interfering with each other.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article “Digital subscriber line”.