xDSL [x-digital subscriber line]


(n.) A family of technologies that transmit digital information, and in some cases analog information, over existing copper-wire pairs for limited distances from the telephone company central office (CO). The “x” is used to denote any of several letters for the xDSL family members. These include asymmetric DSL (ADSL), highbit- rate DSL (HDSL), ISDN DSL (IDSL), single-pair symmetrical services DSL (SDSL), and very-high-bit-rate digital subscriber line (VDSL). All of these services offer subscribers high-speed data transmission downstream and, typically, a lower rate of transmission upstream to the CO.