This ETS specifies the characteristics of an access digital section for 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 Rec.Q512. The requirements of this ETS satisfy network performance requirements of CCITT Rec. G.821 A5E on error performance as well as G.801 and I.350 with regard to availability. This ETS does not specify the requirements of the digital trans-