Integrated Services Digital Network (ISDN) - Signalling System No. 7 (SS7) - Digital cellular telecommunications system (Phase 2+) - Application of ISDN User Part (ISUP) version 3 for the ISDN-Public Land Mobile Network (PLMN) signalling interface - Part 4: Abstract Test Suite (ATS) and Protocol Implementation eXtra Information for Testing (PIXIT) proforma specification (incl. Diskette!!!)