ETSI EN 301 061-6 English Printed Edition English PDF Integrated Services Digital Network (ISDN); Digital Subscriber Signalling System No. one (DSS1) protocol; Generic functional protocol for the support of supplementary services at the b service entry point for Virtual Private Network (VPN) applications; Part 6: Abstract Test Suite (ATS) and partial P

standard published 10/01/1999 by European Telecommunications Standards Institute