UNE-ETS 300646-1ED1

Integrated Services Digital Network (ISDN);Signalling System No.7;Digital cellular telecommunications system (Phase 2);Application of ISDN User Part (ISUP) version 2 for the ISDN-Public Land Mobile Network (PLMN) signalling interface;Part 1: Protocol specification (GSM 09.12 version 4.1.1) (Endorsed by Asociación Espanola de Normalización in December of 2022.)