本国际标准规定了支持呼叫转移的“QSIG”和“H.323”之间的信令互通 企业电信网络（CN）内的补充业务。 “QSIG”是一种信令协议，在专用综合业务交换机（PINX）之间的Q参考点运行 在专用综合服务网络（PISN）内。ISO/IEC 11579-1中定义了Q参考点。PISN提供 向用户提供的电路交换基本业务和补充业务。QSIG在其他标准中有规定，尤其是 ISO/IEC 11572（支持基本服务的呼叫控制）、ISO/IEC 11582（支持基本服务的通用功能协议） 补充服务）和一系列规定个别补充服务的标准。 ISO/IEC 13873规定了 支持呼叫转移服务的QSIG协议。 “H.323”是一组信令协议，用于支持分组网络内的语音或多媒体通信，例如: 一种使用互联网协议（IP）作为其网络层协议（IP网络）的分组网络。H.323信令 协议在IP网络中的端点之间运行，可以通过一个或多个网关守护者间接运行，也可以直接运行。终点 可以是另一个网络的终端或网关。H.323是一个“伞式”建议，指的是各种ITU-T 建议，尤其是建议H.225.0和H.245（基本通信能力）以及 建议H.450.1（支持补充服务的通用功能协议）。 建议H.450.3 指定支持呼叫转移服务的H.323协议。 注:H.450.3仅适用于1998年版本的H.323（也称为H.323版本2）和更高版本。 在ISO/IEC 13873（QSIG）和ITU建议H.450.3（H.323）中，呼叫转移补充业务都是呼叫转移 无条件转发（SS-CFU）、呼叫转发忙（SS-CFB）、呼叫转发无应答（SS-CFNR）和呼叫 偏转（SS-CD）。这些补充服务在呼叫建立期间应用，并将传入呼叫转移到 另一个目的地。 QSIG和H.323之间的互通允许在PISN用户处发起的呼叫在IP网络的用户处终止，或 在IP网络的用户处发起以在PISN的用户处终止的呼叫。 本国际标准规定如下: 其他功能: _从PISN发起的呼叫，目的地为H.323网络的用户，该用户将被H.323网络转移到网络 替代目的地； _源于H.323网络的呼叫，目的地为PISN用户，由PISN转移到备用网络 目的地 _一种呼叫，目的地为PISN的用户，将其转移到另一个目的地，而该另一个目的地位于同一个网络中 H.323网络； _一种呼叫，目的地为H.323网络的用户，以转移到替代目的地，其中该替代目的地 在PISN中。 本国际标准适用于任何可作为采用QSIG的PISN之间网关的互通单元 以及采用H.323的IP网络。

This International Standard specifies signalling interworking between "QSIG" and "H.323" in support of call diversion supplementary services within a Corporate telecommunication Network (CN). "QSIG" is a signalling protocol that operates at the Q reference point between Private Integrated Services eXchanges (PINX) within a Private Integrated Services Network (PISN). The Q reference point is defined in ISO/IEC 11579-1. A PISN provides circuit-switched basic services and supplementary services to its users. QSIG is specified in other Standards, in particular ISO/IEC 11572 (call control in support of basic services), ISO/IEC 11582 (generic functional protocol for the support of supplementary services) and a number of standards specifying individual supplementary services. ISO/IEC 13873 specifies the QSIG protocol in support of call diversion services. "H.323" is a set of signalling protocols for the support of voice or multimedia communication within a packet network, in particular a packet network that uses the Internet Protocol (IP) as its network layer protocol (IP network). H.323 signalling protocols operate between endpoints in an IP network, either indirectly via one or more gatekeepers, or directly. An endpoint can be a terminal or a gateway to another network. H.323 is an "umbrella" recommendation referring to various ITU-T recommendations, in particular Recommendations H.225.0 and H.245 (basic communication capabilities) and Recommendation H.450.1 (generic functional protocol for the support of supplementary services). Recommendation H.450.3 specifies the H.323 protocol in support of call diversion services. NOTE - H.450.3 applies only to the 1998 version of H.323 (also known as H.323 version 2) and to later versions. In both ISO/IEC 13873 (QSIG) and ITU-Recommendation H.450.3 (H.323), the call diversion supplementary services are Call Forwarding Unconditional (SS-CFU), Call Forwarding Busy (SS-CFB), Call Forwarding No Reply (SS-CFNR) and Call Deflection (SS-CD). These supplementary services apply during call establishment and provide diversion of an incoming call to another destination. Interworking between QSIG and H.323 permits a call originating at a user of a PISN to terminate at a user of an IP network, or a call originating at a user of an IP network to terminate at a user of a PISN. This International Standard provides the following additional capabilities: _ a call originating from a PISN and destined for a user of an H.323 network to be diverted by the H.323 network to an alternative destination; _ a call originating from an H.323 network and destined for a user of a PISN to be diverted by the PISN to an alternative destination; _ a call destined for a user of a PISN to be diverted to an alternative destination where that alternative destination is in an H.323 network; _ a call destined for a user of an H.323 network to be diverted to an alternative destination where that alternative destination is in a PISN. This International Standard is applicable to any interworking unit that can act as a gateway between a PISN employing QSIG and an IP network employing H.323.