Brilliant and thanks for reply.
By the way, I found out which pin was activated when they are interconnected. Setting this all up seems to trigger my home center nicely, and I'm able to roll up all my blinds whenever alarms are detected.

Re: Nemaxx smoke alarm WL2

Found this old post and wanted to reply, but it was too old, so I'll create a new.

Very interesting post. I have similar smoke alarms and plan to add Fibaro smart implant to detect alarm activation in my home center whenever one of them are triggered. What I managed to do so far is detecting the alarm activation of one single smoke detector by connecting my implant to its P64 pin as @freynder mentioned. But it doesnt trigger if I interconnect all detectors together and activates one of the other detectors. Is there another pin which detects the interconnection and how did you manage to analyse PCB, finding which chips and pins are relevant?