scope:

This seventh part of EN 300 356 specifies the stage three of the Terminal Portability (TP) supplementary service for the pan-European Integrated Services Digital Network (ISDN) as provided by the European public telecommunications operators by means of the Signalling System No.7 protocol for the ISDN User Part (ISUP). Stage three identifies the protocol procedures and switching functions needed to support a telecommunication service (see CCITT Recommendation I.130 [1]). The present document does not specify the additional protocol requirements where the service is provided to the user via a telecommunications network that is not an ISDN.