ITU-T U.11-1993
洲际电路上供洲际自动中转业务用的用户电报和电路交换公众电报的信号(C型信号)-信令系统之间电报交换具体信令方案
Telex and Gentex Signalling on Intercontinental Circuits Used for Intercontinental Automatic Transit Traffic (Type C Signalling) - Telegraph Switching Specific Signalling Schemes and Interworking between Signalling Systems (Study Group IX) 17 pp