We have a home with a ~20 year old Bosch system, with I believe D636 keypads, which have up to 3 zones terminated at each keypad. Why the home builders in 2002 decided to run the zones there rather than spend a tiny bit more on copper and labor and home run them, I have no idea.

I’m looking at trying to replace the system, because I haven’t found any way to make it “smart”. But I’m hoping to reuse the existing sensors. Looking at my options, the only choice I’ve found is a Honeywell Vista 20p system, with Honeywell 6164US keypads ($3-400 each).

I have the Honeywell system in another house (with the basic keypads, since it has home-runs). It’s basic but works just fine, since there are modern IP/LTE connectors that make it work (I use Eyezon Envisalink, and their monitoring, and have it integrated into HomeKit, and it works excellently, though it is somewhat limiting to just that platform!).

I was curious if there are other options out there? The keypads are not mounted on an electrical box, so taking normal keypads and port expanders wouldn’t be ideal. I could potentially see replacing the keypads with just wireless transmitters, and going with a system like the ProA7Plus, with PROSIXC2W wired -> wireless converters, as they seem to look not-half-bad if they were to be mounted on a wall. However, it says that the power is at 5VDC, and running that on the existing wiring (likely 22/4) isn’t going to work (Specs say 6′ on 22 gauge), and I’d rather not have a tail coming down the wall. So perhaps an older, non-encrypted, but 12V wireless bridge could work (https://www.alarmgrid.com/products/2gig-take-345).

Although, thinking through, if if I have 4-conductor to the keypads, and googling says the Bosch keypads have “3 onboard zones”, I could just jumper the zones onto the 4-wire back to the panel box most likely, and then have a single wireless converter there, or any type of alarm system really that doesn’t rely on hardwired keypads on the wall. The new proa7 seems to have a desktop stand, or there are some app-only alarm systems as well it seems.