ISDN

Integrated Services Digital Network.

Abbreviation for integrated services digital network. An integrated digital network in which the same time-division switches and digital transmission paths are used to establish connections for different services. Note 1: ISDN services include telephone, data, electronic mail, and facsimile. Note 2: The method used to accomplish a connection is often specified: for example, switched connection, nonswitched connection, exchange connection, ISDN connection.