) noun
Acronym for Integrated Services Digital Network. A worldwide digital communications network evolving from existing telephone services. The goal of ISDN is to replace the current telephone network, which requires digital-to-analog conversions, with facilities totally devoted to digital switching and transmission, yet advanced enough to replace traditionally analog forms of data, ranging from voice to computer transmissions, music, and video. ISDN is built on two main types of communications channels: a B channel, which carries data at a rate of 64 Kbps (kilobits per second), and a D channel, which carries control information at either 16 or 64 Kbps. Computers and other devices connect to ISDN lines through simple, standardized interfaces. When fully implemented (possibly around the turn of the century), ISDN is expected to provide users with faster, more extensive communications services. See also