scope:

The present document specifies requirements for the ISDN basic rate UNI including the physical, electrical and functional characteristics and the information exchange with higher layers. This ensures that interface implementations in an ISDN equipment for use with ISDN basic access is portable within Europe with regard to layer 1 interface aspects and that interworking with higher layer protocols for ISDN is supported. The present document is applicable to equipment having interface IA or IB for the connection to the ISDN basic access intended to be installed on customer premises according to ITU-T Recommendation I.411 [9], the present document is for application to interfaces at reference points S, T and S/T (coincident S and T) of the ISDN reference configuration.