ETSI EN 300 267-3 English Printed Edition English PDF Integrated Services Digital Network (ISDN); Telephony 7 kHz, videotelephony, audiographic conference and videoconference teleservices; Digital Subscriber Signalling System No. one (DSS1) protocol; Part 3: Test Suite Structure and Test Purposes (TSS&TP) specification for the user

standard published 08/01/1999 by European Telecommunications Standards Institute