Integrated Services Digital Network (ISDN) - Signalling System No. 7; ISDN User Part (ISUP) version 3 for the international interface - Part 15: Diversion supplementary services [ITU-T Recommendation Q.732, clauses 2 to 5 (1997), modified] (Endorsement of the English version EN 300356-15 V 3.2.2 (1998-08) as German standard)