Question: In a TCH/AFS operation without TFO, what happens when a FACCH needs to be sent during a speech pause, and the preceding frame is not of TX_TYPE="SPEECH_GOOD"?
Option 1: An ONSET frame is signalled to the CHE, followed by the FACCH frame(s), and then a SID_UPDATE if the next frame is of TX_TYPE="SID_UPDATE"
Option 2: A SID_FIRST frame is immediately sent before the FACCH frame(s) without an ONSET frame, regardless of the preceding frame type
Option 3: No action is taken, and the FACCH frame(s) are transmitted without any additional framing to maintain speech pause integrity
Option 4: The system waits for a TX_TYPE="SPEECH_GOOD" frame before transmitting the FACCH frame(s), potentially delaying control channel messages
Explanation: According to the specified behavior for TCH/AFS operations, when a FACCH needs to be sent during a speech pause and the preceding frame is not of TX_TYPE="SPEECH_GOOD", an ONSET frame must be signalled to the Channel Encoder (CHE) followed by the FACCH frame(s). This ensures proper handling of the transition from a non-speech frame to a control channel message during a speech pause. The subsequent transmission of a SID_UPDATE after the FACCH, if the following frame is not "SPEECH_GOOD", maintains the integrity of the speech pause encoding.