scope:

This second edition European Telecommunication Standard (ETS) specifies requirements and test principles for the ISDN 2 048 kbit/s primary rate UNI including the physical, electrical and functional characteristics and the information exchange with higher layers. Compliance with this ETS ensures that, with regard to layer 1 interface aspects, equipment for use with ISDN primary rate access is portable within countries that adhere to this ETS and, furthermore, that interworking with higher layer protocols for ISDN is supported.