Integrated Services Digital Network (ISDN) - Basic Access Interface for Use on Metallic Loops for Application on the Network Side of the NT (Layer 1 Specification) (formerly T1.601-1999 (R2009) )
综合业务数字网(ISDN).在NT网络侧应用的金属环路上使用的基本接入接口(第1层规范)(原T1.601-1999(R2009))