企业通信网络是指在企业内部建立的通信网络，用于实现企业内部的通信和协作。QSIG和SIP是两种常见的企业通信网络协议，它们分别由ITU-T和IETF制定。QSIG是一种基于ISDN的协议，主要用于企业内部的语音通信和数据传输；SIP是一种基于IP的协议，主要用于互联网上的语音通信和视频通信。

由于QSIG和SIP是两种不同的协议，它们之间的信令互通需要进行转换。ISO/IEC 23916:2005标准提供了一种实现QSIG和SIP信令互通的方法，即通过网关进行转换。网关是一种设备，用于连接不同的通信网络，实现不同协议之间的通信。在QSIG和SIP之间建立网关，可以实现两种协议之间的信令互通。

除了信令互通，ISO/IEC 23916:2005标准还介绍了呼叫转移的实现方法。呼叫转移是指在通话过程中将通话转移到另一个终端的功能。在QSIG和SIP之间建立网关后，可以通过网关实现呼叫转移。具体实现方法是，在通话过程中，将呼叫转移请求发送到网关，网关将请求转换为另一种协议的请求，然后将请求发送到目标终端，实现呼叫转移。

ISO/IEC 23916:2005标准的实现可以提高企业通信网络的互通性和灵活性，使得企业内部的通信更加便捷和高效。

相关标准
- ISO/IEC 11579-1:1995 Information technology -- Telecommunications and information exchange between systems -- Private Integrated Services Network -- Inter-exchange signalling protocol -- Call transfer supplementary service
- ISO/IEC 11579-2:1995 Information technology -- Telecommunications and information exchange between systems -- Private Integrated Services Network -- Inter-exchange signalling protocol -- Call transfer supplementary service -- Protocol implementation conformance statement (PICS) proforma
- ISO/IEC 11579-3:1995 Information technology -- Telecommunications and information exchange between systems -- Private Integrated Services Network -- Inter-exchange signalling protocol -- Call transfer supplementary service -- Abstract test suite (ATS) and protocol implementation conformance statement (PICS) proforma
- ISO/IEC 11579-4:1995 Information technology -- Telecommunications and information exchange between systems -- Private Integrated Services Network -- Inter-exchange signalling protocol -- Call transfer supplementary service -- Protocol implementation extra information for testing (PIXIT)
- ISO/IEC 11579-5:1995 Information technology -- Telecommunications and information exchange between systems -- Private Integrated Services Network -- Inter-exchange signalling protocol -- Call transfer supplementary service -- Protocol implementation extra information for testing (PIXIT) for the support of QSIG basic call transfer service