12.053GPPSubscriber Related Call and Event DataTS
Figure B.5 illustrates an incoming call from a fixed network subscriber "A" to a Service Centre directly connected to an MSC within a PLMN network. Examples for services provided by such a Service Centre include Voice Mail services, Operator services etc.
The call is routed to a GMSC within the PLMN (1). The GMSC analyses the dialled digits and routes the call directly to the MSC to which the Service Centre is connected (2).
As HLR interrogation is not required, there will be no HLR Interrogation record. The GMSC shall however, create an incoming gateway record based on the point at which the call entered the network and the destination (Service Centre) of the call.
The MSC then connects the calling subscriber to the service centre. As no mobile subscriber is involved, the MSC will not create an MTC record, however, the MSC shall create a transit Record describing the destination of the call.
The records generated are subsequently transferred to the OS of the PLMN (A).
It should be noted that without the transit record, the MSC would not generate a record for this connection.
Figure B.5: Incoming call to a PLMN service centre