Question: What is a prerequisite for a mobile station to initiate the transmission of application-specific data during an ongoing voice group call in a Voice Group Call Service (VGCS)?
Option 1: The mobile station must be registered with the network for at least 5 minutes.
Option 2: The mobile station must check with the USIM (Universal Subscriber Identity Module) to verify if the subscriber is allowed to transmit application-specific data for the respective group ID.
Option 3: The mobile station must first switch to a dedicated channel from a common channel.
Option 4: The mobile station must receive approval from the VGCS application in the network.
Explanation: This is correct because, according to Voice Group Call Service (VGCS) specifications, a mobile station supporting this feature must verify with the USIM whether the subscriber has permission to transmit such data for the specific group ID involved, ensuring only authorized transmissions occur and maintaining security and adherence to service subscriptions.