The present document specifies a set of technical requirements for Digital Enhanced Cordless Telecommunications (DECT) Fixed Parts (FP) supporting connection, via an ISDN interface, to a network supporting terminal mobility. The standard covers the requirements necessary for the support of Cordless Terminal Mobility (CTM) Phase 1 (Part 1) and for the support of the DECT access to GSM via ISDN interfaces (Part 2). In both of these scenarios, the FT is connected to the network via the alpha interface, as specified in EN 301 144-1 [8].