ISDN Protocol Administrator's and Developer's Guide ... - Intervoice

E1 Transfer MethodsDPNSS 1 Call TransferFor more information onBTNR 188, refer to theBritish Telecom documentDigital Private SignalingSystem No 1 (DPNSS 1).For more information onDPNSS 1, refer to“DPNSS 1 Protocol,”Chapter 6.DPNSS 1 (Digital Private Network Signaling System 1) is defined inBritish Telecom Standard BTNR 188. DPNSS 1 can often be used as asubstitute for ISDN. Call transfers in DPNSS 1 can be accomplishedwith two supplementary services:• Three-Party Service• Route OptimizationThey can also be accomplished through call diversion. (see page 3-8).Three-Party ServiceThe Three-Party supplemental service allows an Omvia Media Server toplace a call to a third party while an existing call is on hold, then connectboth parties within the end PBX. Then it releases the two channels to theOmvia Media Server, which transfers the call.The Hold supplementary service (BTNR 188 Section 12) and the RouteOptimization supplementary service are used in conjunction withThree-Party supplemental service.Route OptimizationThe supplementary service of Route Optimization allows the OmviaMedia Server to use a new connection between two PBXs if anestablished call does not follow the optimum route.The characteristics of Route Optimization call transfer are shown inTable 3-6.Table 3-6. Route Optimization Call Transfer CharacteristicsSpan Type Transfer Type connect UserDLL?E1 Two Line Transfer Yes60001262, First Edition Call Transfer 3-7