DIN EN 300288:2002
通路和终端(AT).有完整八位字节的64kbit/s数字无限制租用专线(D64U).网络接口表示
Accesss and Terminals (AT) - 64 kbit/s digital unrestricted leased line with octet integrity (D64U) - Network interface presentation (Endorsement of the English version EN 300288 V 1.2.1 (2001-07) as German Standard)