On Thursday, 6 February 2020 17:30:44 UTC, ARW wrote:

They also do relay bases should you want to monitor if the alarms are
sounding and switch stuff off. ISTR Matthew uses one to turn his heat
recovery system off in the event of a fire alarm.

Yes, and sends me a text too now! That'd be a scary one to receive, but it does help allay the 'Has my house burnt down?' thoughts I seem to sometimes get when I'm away on holiday!