This Recommendation contains the User-Network Interface (UNI) to UNI testing principles and test specifications for interworking ISDN, non-ISDN and undetermined accesses over international ISUP (ISUP'92 or Q.767). It is intended for tests with ISUP'92, but it is also applicable for combinations between ISUP'92 and ISUP Q.767. For the test scripts, an informal description method is used.