Did not see clues in search and wondering if I go with these people would be nice to Arm- DisArm using HA...
Hi, why would you do that if all this and more can be done with the mobile companion app?
I want to create automation based on presence detection: arm when HA see no one at home and disarm when someone arrives.
Again: all this can be done with HA and the HA mobile companion app given you connect your mobile to HA over the internet by making your server somehow accessible.
What I mean by 'somehow': the easiest way is to subscribe to Nabu Casa Cloud.
With that you get an easy and safe way to connect your mobile.
On top of that you get the best option for voice assistants & you support the project.
Aside of that, there are multiple other ways to achieve that but you have to start tinkering.
Ok, what protocol/ hardware to use between alarm panel (dsc pc1555+m2m) and HA?
well I was hoping that may be HA has similar integration for M2M RControl as is for Honeywell total connect.
And for others looking for a solution I see two options : 1. Integrate Dsc Alarm
2. Emulate M2M function with esp8266 and an optocoupler to pull Zone6 down from 8v to 4v. (5kOhm resistor) That is how Arm-Disarm functionality on DSC PC1555 works: it needs to be configured for "Keyswitch Arm/Disarm" type.