DIN ETS 300356-12:1995-11
Отменен
Integrated Services Digital Network (ISDN) - Signalling System No. 7 - ISDN User Part (ISUP) version 2 for the international interface - Part 12: Conference call, add-on (CONF) supplementary service [ITU-T Recommendation Q.734, clause 1 (1993), modified]; English version ETS 300356-12:1995
