ISO/IEC 17343:2007规定了QSIG和会话启动协议（SIP）之间的信令互通，以支持企业电信网络（CN）（也称为企业网络）内的基本服务。 QSIG是一种信令协议，在专用综合业务网（PISN）内的专用综合业务网交换机（PINX）之间运行。PISN为用户提供电路交换的基本业务和补充业务。QSIG在其他标准中有规定。 注:QSIG的名称来源于它用于Q参考点的信号传输。Q参考点是两个PinX之间的分界点。 SIP是一种应用层协议，用于建立、终止和修改多媒体会话。它通常通过IP进行传输。 电话通话被认为是一种仅交换音频的多媒体会话。 随着公司网络中对电话技术的支持从电路交换技术发展到互联网技术，这两种技术将在一段时间内，甚至几年内，在许多网络中共存。因此，需要能够建立、修改和终止涉及SIP网络中的参与者和QSIG网络中的参与者的会话。此类呼叫由在SIP和QSIG之间执行互通的网关支持。 ISO/IEC 17343:2007规定了基本服务的SIP-QSIG信令互通，这些服务为采用QSIG的PISN和采用SIP的企业IP网络之间的语音、DTMF、传真和调制解调器媒体提供双向传输能力。 互通的其他方面，例如RTP和SDP的使用，将根据相关媒体的类型而有所不同，不在ISO/IEC 17343:2007的范围内。 支持补充业务的呼叫相关和呼叫独立信令不在ISO/IEC 17343:2007的范围内，但支持某些补充业务（例如呼叫转移、呼叫转移）可能是未来工作的主题。 QSIG和SIP之间的互通允许源于PISN用户的呼叫终止于公司IP网络的用户，或源于公司IP网络的用户的呼叫终止于PISN的用户。 采用QSIG的PISN和采用SIP的公共IP网络之间的互通不在ISO/IEC 17343:2007的范围内。然而，ISO/IEC 17343中规定的功能: 当与其他相关功能（例如数字翻译、安全功能等）一起部署时，2007原则上适用于此类场景。 ISO/IEC 17343:2007适用于任何可以充当采用QSIG的PISN和采用SIP的企业IP网络之间网关的互通单元。

ISO/IEC 17343:2007 specifies signalling interworking between QSIG and the Session Initiation Protocol (SIP) in support of basic services within a corporate telecommunication network (CN) (also known as enterprise network). QSIG is a signalling protocol that operates between Private Integrated services Network eXchanges (PINX) within a Private Integrated Services Network (PISN). A PISN provides circuit-switched basic services and supplementary services to its users. QSIG is specified in other Standards. NOTE The name QSIG was derived from the fact that it is used for signalling at the Q reference point. The Q reference point is a point of demarcation between two PINXs. SIP is an application-layer protocol for establishing, terminating, and modifying multimedia sessions. It is typically carried over IP. Telephone calls are considered a type of multimedia session where just audio is exchanged. As the support of telephony within corporate networks evolves from circuit-switched technology to Internet technology, the two technologies will coexist in many networks for a period, perhaps several years. Therefore, there is a need to be able to establish, modify, and terminate sessions involving a participant in the SIP network and a participant in the QSIG network. Such calls are supported by gateways that perform interworking between SIP and QSIG. ISO/IEC 17343:2007 specifies SIP-QSIG signalling interworking for basic services that provide a bi-directional transfer capability for speech, DTMF, facsimile, and modem media between a PISN employing QSIG and a corporate IP network employing SIP. Other aspects of interworking, e.g., the use of RTP and SDP, will differ according to the type of media concerned and are outside the scope of ISO/IEC 17343:2007. Call-related and call-independent signalling in support of supplementary services is outside the scope of ISO/IEC 17343:2007, but support for certain supplementary services (e.g., call transfer, call diversion) could be the subject of future work. Interworking between QSIG and SIP permits a call originating at a user of a PISN to terminate at a user of a corporate IP network, or a call originating at a user of a corporate IP network to terminate at a user of a PISN. Interworking between a PISN employing QSIG and a public IP network employing SIP is outside the scope of ISO/IEC 17343:2007. However, the functionality specified in ISO/IEC 17343:2007 is in principle applicable to such a scenario when deployed in conjunction with other relevant functionality (e.g., number translation, security functions, etc.). ISO/IEC 17343:2007 is applicable to any interworking unit that can act as a gateway between a PISN employing QSIG and a corporate IP network employing SIP.