DIN EN 300121:2004-07
Действует
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.767 Amendment 1 (2002), modified] (Endorsement of the English version EN 300121 V1.2.1 (2003-07) as German standard)
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