Question: When a Mobile Equipment (ME) encounters a permanent problem with USIM interaction for call control or MO short message control, what does the first byte value '01' in the additional information indicate?
Option 1: The type of request has changed since the initial setup.
Option 2: Action not allowed due to current call/message control state.
Option 3: No specific cause can be identified for the problem.
Option 4: The ME is currently processing another call/message control request.
Explanation: According to the specifications, when the ME provides additional information for a permanent problem with USIM interaction for call or MO short message control, the first byte value '01' specifically indicates that the action requested by the USIM is not allowed. This could be due to various reasons such as the current state of call/message control (e.g., another call is in progress, or a message operation is already underway), highlighting the importance of understanding the nuances of telecom protocol interactions for effective network management and user experience.