I have had a ABUS Smartvest Alarm system for many years - works absolutely reliably but lacks an interface to HA. Based on an idea in another forum here is what I did to integrate Smartvest with HA -
Use the “radio key” which is mostly included with the Smartvest system (never needed mine, and was therefore for free for this project)
Pry open the plastic case with a broad screw driver (press fit), and pry open the radio PCB
There are four push button switches for four actions (arm, disarm, camera, panic) with solder points that are accessible reasonably well
Solder two thin wires (e.g. jumper wire) per push button with a fine soldering iron
Connect the wires to a Zigbee relay. To be on the safe side, get a relay with one contact per unit. ZG-001 for example. There are Zigbee modules with upto four contacts but some gateways (like CONBEE) do not support multiple endpoints
Use the switch in HA to disarm (short pulse), Arm (short pulse) or internal Arm (long pulse)
thank you for sharing this post. I just want to contribute how I realized the connection based on your description.
I wanted a matter capable smart switch with 4 channels which made it a litte bit tricky as there aren’t to many devices out there yet with that capability.
Anyhow this is how it worked for me:
a Freedompro LB0104-C 12V smart switch with 4 channels (as there are 4 buttons on the ABUS Smartvest FUBE35001A)
4 12V DC relais with a dry contact outgoing switch
This is how it looks like (not nice yet but working
I have one correction though… as I see it, it is not possible to trigger an internal alarm with a longer pulse of e.g. 3.5 seconds - the rest works fine