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11.8 ISUP SIGNALING IN THE INTERNATIONAL NETWORK 319from the calling ISDN user or subscriber, it initiates the release of the networkconnection.11.8 ISUP SIGNALING IN THE INTERNATIONAL NETWORK11.8.1 IntroductionIn the mid-1980s, representatives from AT&T, British Telecom International, andKDD (Japan) started to define a version of ISUP for use in the internationalnetwork [8]. International ISUP has been installed in international switchingcenters (ISCs) of many countries and is used for call control on a large number ofinternational trunk groups.International ISUP, as documented in Rec. Q.767 [9], is a subset of ITU-TRecommendations Q.762–Q.764. Address signaling is en-bloc only (the IAMsalways include the complete called party number). End-to-end signaling and callforwarding are not available.11.8.2 Service Supported by International ISUPIn addition to bearer services and the transfer of parameters for TE selection at thecalled ISDN user, international ISUP supports the following supplementaryservices: “calling line identification presentation/restriction,” “connected lineidentification presentation/restriction,” “user-to-user signaling,” and “closed usergroup service.” This support is limited to the transfer of parameters associatedwith these services across the international network.11.8.3 Messages Not ProvidedOf the messages listed in Sections 11.2.3, 11.6.7, and 11.6.8, international ISUPdoes not provide:. Information (INF). Information Request (INR). Pass-Along (PAM)11.8.4 Parameters Not ProvidedOf the parameters described in Sections 11.2.4 and 11.6.8, international ISUP doesnot provide:. Call reference (Par.5). Information indicators (Par.15). Information request indicators (Par.16)