Has anyone been able to connect this thermostat to ST?
As far as I know, OneLink is a proprietary communication protocol that First Alert created to link their smoke alarms together. I don’t know if it’s the same for the thermostat.
Is it WiFi, Bluetooth, ZigBee, Z-Wave???
The current version of the thermostat is Wi-Fi to first alert’s “Skyport” cloud service. It has an app, but no open API. It doesn’t integrate with anything, including the one link smoke detectors from the same company.
That said, The new generation, not yet available for purchase, is going to be home kit compatible. They just released the HomeKit version of the smoke alarms, and the other one link devices are all being transitioned to HomeKit over the next 12 months or so.
Note there still won’t be an open API, and it probably still won’t work with SmartThings, but by the end of next year you may be able to buy a one link thermostat that will integrate with the one link smoke detectors, the safe, the air quality sensor, and other HomeKit capable devices from other brands.
It’s wifi. No idea if it used other protocols.