Question: What is a prerequisite for triggering the MSC Server assisted mid-call feature during PS-CS Access Transfer to preserve mid-call services without requiring UE's ICS capabilities?
Option 1: The MSC Server, SCC AS, and UE must all support the MSC Server assisted mid-call feature.
Option 2: Only the MSC Server needs to support the MSC Server assisted mid-call feature for activation.
Option 3: The UE must have active sessions using the Conference service for the feature to be triggered.
Option 4: PS-CS Access Transfer can only occur if all network elements support ICS capabilities.
Explanation: For the MSC Server assisted mid-call feature to be triggered and successfully preserve mid-call services (such as inactive sessions or those using the Conference service) during a PS-CS Access Transfer without relying on the UE's ICS (IMS Centralized Services) capabilities, it is crucial that all involved parties - namely the MSC Server, the SCC AS (Service Centralization and Continuity Application Server), and the UE (User Equipment) itself - support this specific feature. This ensures seamless continuity of services across different access networks.