digital subscriber line

digital subscriber line
    n 1: a generic name for digital lines that are provided by
         telephone companies to their local subscribers and that
         carry data at high speeds [syn: {digital subscriber line},
         {DSL}]
    

Digital Subscriber Line
Digital Subscriber Loop
xDSL

   <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.

   (http://cyberventure.com/~cedpa/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)