NF Z82-084-1995
综合服务数字网络(ISDN).可用于3.1kHz音频信息传送的电路方式结构的载体服务种类.端对端兼容性所必需的终端要求
Integrated Services Digital Network (ISDN). Circuit mode structured bearer service category usable for 3,1 kHz audio information transfer. Terminal requirements necessary for end-to-end compatibility.