What does a trouble signal indicate?

A trouble signal is a critical indication within a fire alarm system, specifically pointing to a fault or malfunction in the fire-alarm equipment that needs to be addressed to ensure the system's effectiveness and reliability. This signal alerts users or monitoring personnel that the equipment is not functioning within the designated parameters, which may compromise safety and response capabilities in the event of a fire.

In contrast, a normal operational check represents regular functioning of the fire system, while the activation of an alarm due to smoke pertains to an actual fire condition, not an equipment issue. Lastly, a test signal sent during maintenance checks is a proactive measure that does not indicate a fault but rather is a verification process to ensure the system is working correctly. Therefore, recognizing a trouble signal is essential as it demands attention and timely intervention to maintain the integrity of the fire alarm system.