Integrated Services Digital Network (ISDN) - Call Forwarding No Reply (CFNR) supplementary service - Service description (Endorsement of the English version EN 300201 V 1.2.1 (2001-05) as German standard)— 1 стр.
Integrated Services Digital Network (ISDN) - Call Forwarding No Reply (CFNR) supplementary service - Service description; English version ETS 300201:1994
Integrated Services Digital Network (ISDN); Call Forwarding No Reply (CFNR) supplementary service - Service description; English version ETS 300201:1995/A1:1996
