DIN ETS 300543-2001 数字移动电话远程通信系统(阶段2).转呼补充服务.2级 (英文版本核准本 ETS 300543:1997-01 作为德国标准)
Digital cellular telecommunications system (Phase 2) - Call Forwarding (CF) supplementary services - Stage 2 (Endorsement of the English version ETS 300543:1997-01 as German standard)