OENORM EN 300267-6 V 1.2.6
Integrated Services Digital Network (ISDN) - Telephony 7 kHz, videotelephony, audiographic conference and videoconference teleservices - Digital Subscriber Signalling System No. one (DSS1) protocol - Part 6: Abstract Test Suite (ATS) and partial Protocol Implementation eXtra Information for Testing (PIXIT) proforma specification for the network (incl. Diskette!!!)