DIN EN 301133:2000
综合业务数字网(ISDN).选择呼叫转移(SCF)补充业务(无条件、占线和无响应).业务描述
Integrated Services Digital Network (ISDN) - Selective Call Forwarding (SCF) supplementary services (unconditional, busy and no reply) - Service description (Endorsement of the English version EN 301133 V 1.1.1 (1998,10) as German standard)