ITU-T X.321-1996
一般安排之间的互联互通电路交换的公用数据网络(CSPDNS)和综合服务数字网络(ISDNS)提供的数据传输服务
General Arrangements for Interworking between Circuit-Switched Public Data Networks (CSPDNs) and Integrated Service Digital Networks (ISDNs) for the Provision of Data Transmission Services - Series X: Data Networks and Open System Communication Interworki