If no message is received at a detector, what can the crew request to hear the detector voice message again?

The correct response of requesting the detector voice message again is represented by using the code 001. This code is specifically designated for the purpose of prompting the system to replay the last voice message from the detector. Understanding this code is essential for crew members as it directly correlates to operational procedures when there has been a lack of feedback from the detector, ensuring safety and proper communication during transit.

The other codes, while they may be meant for different functions or requests, do not relate to the playback of the detector's voice message. This highlights the importance of familiarity with the specific codes used in operational scenarios, as they aid in efficient and effective communication within the crew and help maintain safety protocols.