ETSI PRETS 300 485-1995 综合业务数字网(ISDN).1号数字用户信令系统(DSS1)和7号信令系统ISDN用户部分(ISUP)中的定义和使用理由以及位置(ITU-T建议Q.850(1993),修正本)
Integrated Services Digital Network (ISDN); Definition and Usage of Cause and Location in Digital Subscriber Signalling System No. One (DSS1) and Signalling System No. 7 ISDN User Part (ISUP) (ITU-T Recommendation Q.850 (1993), Modified)