UNE-EN 300121V1.2.1

Integrated Services Digital Network (ISDN);Application of the ISDN User Part (ISUP) of ITU-T Signalling System No. 7 (SS7) for international ISDN interconnections (ISUP version 1) Amendment 1: International Emergency Preference Scheme (IEPS) service [ITU-T Recommendation Q.767Amendment 1 (2002), modified] (Endorsed by Asociación Espanola de Normalización in July of 2021.)