Question: Under what conditions must the anchor MSC start the 'no activity' timer for a Voice Group Call Service (VGCS)?
Option 1: When uplink is free, no dispatcher is connected, no short message is waiting to be sent, and no application-specific data are waiting to be relayed.
Option 2: Immediately after a dispatcher joins the ongoing group call.
Option 3: Upon receiving an uplink request from any User Equipment (UE) in the group.
Option 4: When the anchor MSC completes the distribution of a short message to the voice group call.
Explanation: The correct answer is Option 1 because, according to the specifications for Voice Group Call Service (VGCS), the anchor MSC must start the 'no activity' timer only when all specific conditions are met simultaneously: the uplink is free, there's no connected dispatcher, no pending short messages for the group, and no queued application-specific data. This ensures the timer reflects periods of genuine inactivity within the group call.