(ISDN, Integrated Services Digital Network, N-ISDN, B-ISDN) A single network capable of carrying several different types of service, based on voice, data, still or moving image - by means of digital transmission techniques. The ISDN currently being deployed in Europe carries a communication of up to 2 Megabits/second (Narrowband ISDN). Future networks will carry higher speed communications (Broadband ISDN).