Alarm system terminal with a known protocol?

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MindBender
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Alarm system terminal with a known protocol?

Post by MindBender »

Hi guys,

My house came with an alarm system. It's made by an unknown Belgian brand called 'Eurotec', which seems to have gone out of business. I had a failing battery and now the names of my detector loops are gone. Those settings can only be restored by a proprietary computer program, using a proprietary cable (which is probably just a TTL-RS232 level shifter), costing over 600 Euro. So that's not going to happen.

On the other hand, I've been looking voor affordable wall-mounted terminals to control my domotica system. A full color touch-screen version is what springs to mind, but a simple 2x16 character LCD with a 3x4 keyboard would do the trick too. And that's exactly what my alarm system terminals are!

So I have been poking around these terminals. Using an oscilloscope I quickly found out that it uses a 2-wire multi-drop protocol wil RS485 signalling levels. The bit rate was a bit odd: 16.667bit/s, but using Linux I was able to manually set the bit rate devisor. So I have bought myself an Advantech Adam 4520 RS232-RS485 converter and watched the traffic. The past three evening I have spent counting bits on the oscilloscope, but nothing makes sense. I strongly suspect these critters are deviating from the standard UART transmission. I see a lot of break conditions, and it seems they are transmitting over 12 bit symbols. I have even considered the 9 data bit Philips variety, but that doesn't compute either. Now I am considering to write my own firmware for their internal PIC processor, but that's a lot of work.

<b>So my question is:</b> Does anybody know about alarm system terminals with an LCD and a keyboard and a known protocol, currently on the market? Preferably not wireless and with a price lower than 100 Euro.
Francois
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Alarm system terminal with a known protocol?

Post by Francois »

Mindbender,

to answer your question. You might consider taking a different approach just like I did. Several years ago I choose to instal a professional alarm system built on an Aritech CD34 panel, this was before I ever thought of hooking it up to my domotica system.


I recently looked at the integration and considered the following options:
- trying a rs-232 like connection, not an option since the Aritech CD34 has no real interface and uses a proprietary -not published- protocol
- replacing the panel by something else, not an option since it works great, never generate any false alarms and I am very happy with it.
- interface in a different way.

I choose the last option. Let me explain.

I generally have three needs when interfacing with the alarm panel:

1. controlling the status "ARMED", "OFF" and "PARTIALLY ARMED". This can all be done by means of two switches (NC contacts) that should interfaced to the PC and be controlled by the domotica system
2. Reading the status "Normal operation", "Sabotage" and "Alarm". The panel provides outputs signals on a 12v level, these outputs should be interfaced to the PC and the domotica system.
3. reading the inputs ("PIR" and "REED CONTACTS"). This one is a bit more tricky. The panel uses sabotage aware contacts that can distinguish four states. Open: somebody cut the wire-> sabotage, Closed : somebody shorted the wire, 4k7 ohm: the contact is closed--> normal operation and 10K ohm: the contact is trigggerd. The corresponding voltages should be read and converted to the desirered states and again fed to the domotica system.

To get the job done I:
1. Bought a DigiBee+ board with USB connection to the PC. This board has 16 Digital inputs, 16 Digital ouputs and 4 Analog inputs
2. Bought a Velleman K6714-16 relay interface board to establish electrical isolation. (I considerd building it my self but this board is cheap..)
3. Connected the Velleman board to the DigiBee outputs and the appropriate Alarm panel inputs. --> I can now arm and disarm using Homeseer
4. Built an interface based on 16 optocouplers that protects and electrically isolates the digibee inputs.
5. Connected sevral a;arm panel outputs to the optocoupler inputs --> Eanbles be to detect various alarm conditions.
5. Used a AVR Tiny programmable controller with 10 channels that are connected in parallel to the alarm inputs. The controller inputs read the input voltages and converts them to binary outputs (contact closed. contact open) -->All alarm contatc are now available in Homeseer as Status Only devices
7. Wrote a little visual basic interface that connects the Digibee board (comes with a DLL) and my HomeSeer software.

I have finished steps 1-4 and 6 and am currently working on 6. to finish it off. It had me busy for some time but I think it's a quite reliable option that does what I want and leaves the professional alarm panel that I am very heappy with, working independently.

Checkout Marktplaats for Aritech CD34 panels, they come for about 100 euro and with that you buy top quality professional stuff.

Goodluck,

Francois
MindBender
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Alarm system terminal with a known protocol?

Post by MindBender »

Thank you for your response, Francios. The CD34 look nice indeed. But the proprietary protocol is a real disadvantage.

The purpose of my project is not to control my alarm system. Soon I will chuck the alarm system in the bin and let my domotica system take over its security functions. But since I have three control panels installed in my house, it seemed like a nice idea to put them to my own use. Unfortunately the Eurotec panels use a very un-standard serial protocol which cannot be read by a standard UART. But the idea of having a simple and relatively cheap wall terminal with a simple display and keyboard stuck.

I want to be able to interface an alarm panel to (a serial port of) my Domotica system. I want to be capable of putting my own (menu) text on this display and to read out any keys pressed. This way I can use the panel to switch on and off my Domotica system's security functions, but I can also tell the system I'm leaving the house so it can turn off all lights an lower the temperature.
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