Integrated Services Digital Network (ISDN) - Signalling System No. 7 - Signalling Connection Control Part (SCCP) (connectionless and connection-oriented class 2) to support international interconnection - Part 3: Abstract Test Suite (ATS) and partial Protocol Implementation eXtra Information for Testing (PIXIT) proforma specification (Endorsement of the English version ETS 300009-3:2000 as German standard)