Private Integrated Services Network (PISN) - Specification, functional model and information flows - Private User Mobility (PUM) - Call handling additional network features [ISO/IEC 17877 (2000) modified] (Endorsement of the English version EN 301657 V1.2.1 (2003-06) as German standard)
专用综合业务网(PISN).规范 功能模型和信息流.专用用户移动性(PUM).呼叫处理附加网络特性[ISO/IEC 17877(2000)修改](认可英文版EN 301657 V1.2.1(2003-06)为德国标准)