I added a 12 zone interface kit to my GE Concord 4. I have a large installation in my alarm system so did not want to scrap it. I have nearly every add-on option card including the voice board. I'm using 9 wired zones as well as 4 wireless zones within the GE panel. I've added the key arm/disarm function. Already on my panel I was running a relay that trips 8 floodlight around the house. I've got two keypads and 4 sirens with a strobe. 3 PIR sensors and 2 smokes. I have the output expansion card giving me a total of 5 onboard relays. I'm using the relay with my kit to drive the key switch, but I'm sure I will find a use for the second relay :) I still need to debug a few things, but everything seems to be working for the most part. I'm using smart things with homebridge to dump everything into Homekit for Apple. So Siri can control my alarms. Would have liked to have direct HomeKit integration as I am having to go through essentially 2 cloud services and 2 hubs to get there.
Pictures posted are the before picture and the 2 after pics.