CCITT Rec. F.73 (11/1988) – OPERATIONAL PRINCIPLES FOR COMMUNICATION BETWEEN TERMINALS ON TELEX NETWORKS AND DATA TERMINAL EQUIPMENT ON PACKET SWITCHED PUBLIC DATA NETWORKS 
1 Introduction
2 Operational outline
3 Call set-up procedures
    3.1 Telex to PSPDN direction
    3.2 PSPDN to telex direction
4 Text transfer phase
    4.1 Telex to packet
    4.2 Packet to telex
    4.3 Answerback formats and WRU processing
    4.4 Call clearing