Abbreviation for integrated services digital network. A proposed international
all-digital communication network that will carry voice, video, facsimile, and
computer data, plus other services, using common underlying facilities and
interfaces. The ISDN is envisioned as a single system capable of handling all
PTT/common-carrier communication traffic. As currently proposed, ISDN is based on
64 kilobit per second digital and circuit-switched communication networks.