Question: When is the ENVELOPE (EVENT DOWNLOAD – Data Connection Status Change) command used to inform the UICC in a terminal supporting class 'e'?
Option 1: Upon receipt of a SET UP EVENT LIST command from the UICC.
Option 2: During the initial power-on sequence of the ME.
Option 3: When the UICC requests a status update using a STATUS COMMAND.
Option 4: Upon detection by the ME of a change in the data connection status, if the event is part of the current event list.
Explanation: This option is correct because the terminal (ME) notifies the UICC using the ENVELOPE command when it detects a change in the data connection status, provided that this event is included in the current event list. This ensures timely updates to the UICC about changes in the data connection, crucial for managing and controlling network resources and services effectively.