Broadband Integrated Services Digital Network (B-ISDN) - Digital Subscriber Signalling System No. two (DSS2) protocol; Connection characteristics; Peak cell rate modification by the connection owner - Part 4: Abstract Test Suite (ATS) and partial Protocol Implementation eXtra Information for Testing (PIXIT) proforma specification of the user (Endorsement of the English version EN 301001-4 V 1.1.3 (2000-10) as German standard)