Provides the characteristics of an access digital section for the Integrated Services Digital Network (ISDN) primary rate access between the user-network interface (at the T reference point, defined in ETS 300 011 [1]) and the local exchange (at the V.3 reference point, defined in CCITT Recommendation Q.512 [4]) supporting the primary rate interface channel structure defined in CCITT Recommendation 1.412 [3] and ETS 300 011 [1] and the additional functions required for operation and maintenance of the access digital section according to ETR 001 [2], Option 2.