Integrated Services Digital Network (ISDN) - Signalling System No. 7; ISDN user Part (ISUP) version 3 for the international interface - Part 14: Explicit Call Transfer (ECT) supplementary service [ITU-T Recommendation Q.732, clause 7 (1996), modifiziert] (Endorsement of the English version EN 300356-14 V 3.1.3 (1998-08) as German standard)