I see that some of Maretron’s SIM100 accessories have built in “trouble relays”; what is a trouble relay and why is it important?

Trouble relays are being integrated into more and more safety and security equipment to provide added safety and security features. For example, a trouble relay can act as power supervision device. In this case, if the power is accidentally turned off to a safety device like a smoke detector, then the security system can indicate that the power has been disconnected and that the area is no longer being monitored for smoke. This is true for security devices as well. For example, if a burglar cuts the power connection to a motion detector, then the system is able to indicate a loss of power and that a particular area is no longer being monitored for motion. Trouble relays can also indicate that a detector has failed its self-diagnostics and isn't capable of performing its monitoring function. Without a trouble relay, a detector might have its power inadvertently removed, its electronics fail, or its sensor worn out with nobody realizing that critical monitoring functions are going unmonitored. Check the manufacturing data sheets of all your safety and security detectors to see what specific functions the trouble relays provide for those detectors.