alarm panel keypad protocol and I/F

dan king · Joined: 22 Sep 2003 Posts: 119

Has anyone interfaced a pic with a home alarm panel or keypad and might be able to share the code to communicate with the panel? I have read various posts where the interface on some has been described as rs-232 or some variant of that?

I am thinking of building an interface to my home alarm panel in a house that I am selling. I would like to read the messages generated by the panel so when any zones trigger I can send an SMS to my phone. I have had trouble with realtors leaving the house unlocked after a showing so if I know they have been there I can stop by and lock up.

I already have the SMS side covered as I built a unit connected to a thermostat so if the temperature dropped below the setpoint I would receive a text. I'm in NewEngland and our winters are pretty cold so that provided me some comfort that my heating and plumbing pipes wouldn't freeze if the heating system failed.

Anyhow, any info or sample code would be appreciated. I typically use PIC18F2553 parts and CCS ver 4.074.

Thanks in advance,

Dan

ezflyr · Joined: 25 Oct 2010 Posts: 1019 Location: Tewksbury, MA

Hi Dan,

I Googled "Alarm Panel Keypad Protocol" and got a number of pretty high quality hits, including a Hackaday posting with a lot of code in 'C'. The 'solution' is likely to be vendor specific, so even if you don't find exactly what you need, a number of the sites I found show the methodology employed to figure out the interface specifics and the protocols used. I also recall a Circuit Cellar article 'Alarming The Alarm' that basically did exactly what you want to do. This came out on the mid 90's, but was reprinted as a 'classic' in the past year or so. If you can't find it, send me a PM and I'll dig it out, scan it, and send it to you.

In my case, my Caddx Network X already had a native serial port sending status messages, so I just had to intercept those and decode them. As you say, it sure provides some peace-of-mind when I'm away from my vacation home during the winter months.

John

dan king · Joined: 22 Sep 2003 Posts: 119

Hi John,

Thanks for the circuit cellar tip. I'll search for that. I saw a few hits as well for the search but hoping for a jumping off point if someone had already worked through something similar since I'm not near the panel.

Thanks,

Dan

temtronic · Posted: Fri May 16, 2014 8:46 am

John's right about the 'vendor specific' interface !

It's been on my 'todo' list for about 5 years....

First step was to build a 'sniffer' PIC..something to capture the real data(ones and zeros) as I pressed the keypad buttons.and display the data. The interface is RS-485 I think for Ademco panels..though it's been awhile.
Google should realy be great at this cause you aren't the first to want to do it !

jay

gpsmikey · Joined: 16 Nov 2010 Posts: 588 Location: Kirkland, WA

I think the first thing I would do is grab a scope and look at the signal lines - are they RS-232 levels or 0-5v or ? Also gives you a chance to figure the baud rate with the scope. That should at least give you a good starting point for a "sniffer" or something to grab data.

mikey
_________________
mikey
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