Question: In a SIM-less emergency call scenario, what determines the format and structure of the non-dialable callback number used to identify the target UE (User Equipment)?
Option 1: Global standards defined by 3GPP for all regions
Option 2: The type of emergency service being requested (e.g., police, ambulance)
Option 3: National or regional regulations
Option 4: Manufacturer specifications based on UE model
Explanation: In the context of telecommunications, especially for emergency services, regulatory compliance is crucial. The format and structure of non-dialable callback numbers, which are used in specific scenarios like SIM-less or non-registered (U)SIM emergency calls, would logically be subject to national or regional regulations to ensure seamless integration with existing emergency response systems and to accommodate local legal requirements. This approach allows for flexibility and adaptability to the unique needs of different regions while maintaining the integrity of emergency services.