UNE-EN 301815-4V1.1.1

Broadband Integrated Services Digital Network (B-ISDN);Digital Subscriber Signalling System No. two (DSS2) protocol;Quality of Service class and parameters indication at call/connection establishment;Part 4: Abstract Test Suite (ATS) and partial Protocol Implementation eXtra Information for Testing (PIXIT) proforma specification for the user (Endorsed by Asociación Espanola de Normalización in December of 2021.)