Can I use the SIM100 to monitor Carbon Monoxide (CO) detectors?

Yes, you can use the SIM100 to monitor Carbon Monoxide (CO) detectors as long as the detector has an auxiliary contact. Maretron offers a CO detector ( https://www.maretron.com/support/manuals/CO-CO1224T%20Installation%20Instructions%201.1.html ) The CO-CO1224T carbon monoxide detector even has a trouble relay, which can be used to indicate several important failure modes including:

1. power lost to the detector
2. detector has reached the end of its useful life
3. power leads or auxiliary contact wires connected to the SIM100 have been cut or corroded and fallen off