美利体育登录入口官网:ITU-T Q.86.4 FRENCH-1997
第2阶段.收费补充业务的描述.国际免费电话业务(IFS).系列Q:交换和信令.综合业务数字网(ISDN)业务的功能和信息流.11号研究组.22pp
Stage 2 Description for Charging Supplementary Services: International Freephone Service (IFS) - Series Q: Switching and Signalling Functions and Information Flows for Services in the ISDN - Supplementary Services Study Group 11; 22 pp