ISO/IEC 21990:2002现行
Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Inter-exchange signalling protocol - Short message service
出版：International Organization for Standardization
专家解读视频
KS X ISO/IEC 21990:2005 - Identical
KS X ISO/IEC 21990:2013 - Identical
DIN EN 301991 (2004-03) - Identical
CSA ISO/IEC 21990:2004 (R2017) - Identical
NEN ISO/IEC 21990:2002 - Identical
ONORM EN 301991:2003 - Identical
