Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric digital subscriber line (ADSL), the most commonly installed DSL technology, for Internet access.

<communications, protocol> (DSL, or Digital Subscriber Loop, xDSL - see below) A family of digital telecommunications protocols designed to allow high speed data communication over the existing copper telephone lines between end-users and telephone companies. When two conventional modems are connected through the telephone system (PSTN), it treats the communication the same as voice conversations. This has the advantage that there is no investment required from the telephone company (telco) but the disadvantage is that the bandwidth available for the communication is the same as that available for voice conversations, usually 64 kb/s (DS0) at most. The twisted-pair copper cables into individual homes or offices can usually carry significantly more than 64 kb/s but the telco needs to handle the signal as digital rather than analog. There are many implementation of the basic scheme, differing in the communication protocol used and providing varying service levels. The throughput of the communication can be anything from about 128 kb/s to over 8 Mb/s, the communication can be either symmetric or asymmetric (i.e. the available bandwidth may or may not be the same upstream and downstream). Equipment prices and service fees also vary considerably. The first technology based on DSL was ISDN, although ISDN is not often recognised as such nowadays. Since then a large number of other protocols have been developed, collectively referred to as xDSL, including HDSL, SDSL, ADSL, and VDSL. As yet none of these have reached very wide deployment but wider deployment is expected for 1998-1999. Digital Subscriber Linecedpa/databus-issues/v38n1/xdsl.html">http://cyberventure.com/Digital Subscriber Linecedpa/databus-issues/v38n1/xdsl.html. 2Wire DSL provider lookup (http://2Wire.com/). ["Data Cooks, But Will Vendors Get Burned?", "Supercomm Spotlight On ADSL" & "Lucent Sells Paradine", Wilson & Carol, Inter@ctive Week Vol. 3 #13, p1 & 6, June 24 1996]. (2001-04-30)

Digital Subscriber Line

Dialogue Scripting Language (Reference: DCE, UIL)

1. <communications> Digital Subscriber Line. 2. <language> Digital Simulation Language. 3. <language> Denotational Semantics Language. (1996-10-13)

Distributed Service Logic (Reference: IN)

Digital Subscriber Line (Reference: DSL)

Digital system Specification Language (Reference: HDL)

<communications, protocol> (ADSL, or Asymmetric Digital Subscriber Loop) A form of Digital Subscriber Line in which the bandwidth available for downstream connection is significantly larger then for upstream. Although designed to minimise the effect of crosstalk between the upstream and downstream channels this setup is well suited for {web browsing} and client-server applications as well as for some emerging applications such as video on demand. The data-rate of ADSL strongly depends on the length and quality of the line connecting the end-user to the telephone company. Typically the upstream data flow is between 16 and 640 kilobits per second while the downstream data flow is between 1.5 and 9 megabits per second. ADSL also provides a voice channel. ADSL can carry digital data, analog voice, and broadcast MPEG2 video in a variety of implementations to meet customer needs. ["Data Cooks, But Will Vendors Get Burned?", "Supercomm Spotlight On ADSL" & "Lucent Sells Paradine", Wilson & Carol, Inter@ctive Week Vol. 3 #13, p1 & 6, June 24 1996]. See also Carrierless Amplitude/Phase Modulation, {Discrete MultiTone}. ADSL Forum (http://adsl.com/). (1998-05-18)