DIN EN 301247-2003 数字蜂窝式电信系统(相位2).增强全速率语音通信信道的适度噪声状况
Digital cellular telecommunications system (Phase 2) - Comfort noise aspects for Enhanced Full Rate (EFR) speech traffic channels (GSM 06.62 version 4.0.1) (Endorsement of the English version EN 301247 V 4.0.1 (1997-12) as German standard)