ETSI EN 300 899-4 English Printed Edition English PDF Final draft Version 1.1.1Integrated Services Digital Network (ISDN); Signalling System No.7 (SS7); Interworking between ISDN User Part (ISUP) version 2 and Digital Subscriber Signalling System No. one (DSS1); Part 4: Abstract Test Suite (ATS) and partial Protocol Implementation eXtra Information for

standard published 01/01/2002 by European Telecommunications Standards Institute