Peter wrote:

>On Tue, 17 Jan 2006, Herbert Graf wrote:
>
>  
>
>>On Tue, 2006-01-17 at 08:57 -0500, Shawn Yates wrote:
>>    
>>
>>>Can anyone tell me where I can find the specifications for having an
>>>alarm panel report to a central monitoring station?  I am looking for
>>>the Contact ID protocol to be exact.  Any help is appreciated.
>>>      
>>>
>>I may be wrong, but considering how competitive that market is, I'm
>>quite certain that the protocols are all proprietary and not compatible
>>with each other, and are surely not something you are meant to be able
>>to find in the public domain.
>>    
>>
>
>Most simpler systems dial into the center and send DTMF codes. One can 
>program just about anything to be sent.
>
>Peter
>  
>
Although many proprietary alarm protocols have come and mostly gone, the 
three most popular remaining are 4x2, Ademco Contact  ID and SIA protocols.

4x2 uses pulsed tones to send 4 (account number) and 2 (alarm signal) 
hex digits at 10, 20 or 40 pps.
Ademco Contact ID sends 15 (information) and 1(checksum) DTMF digits 
representing account number, event code and zone number etc.
SIA sends info using half duplex 300 or 1200 baud FSK the information it 
send can be quite diverse including the capability of being bidirectional.

Most alarm panels on the market today have the capability of being 
programmed to send at least two and sometimes all three of these formats.

Randy

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