Re: Help understanding CID protocol

[Randy Mass <rrmass@xxxxxxxxx>]

ymg200@xxxxxxxxxx wrote:
> My goal is to equip the new house with alarm system which is monitored
> by the central station. I am new to security systems, but once I
> started learning about them, my DIY personality started leaning
> towards building a system myself.
> By doing some research in this discussion group I learned that alarm
> systems communicate with the monitoring station by sending CID
> signals. If CID is a DTMF sequence, can I generate it using any DTMF
> encoder? If I know the CID format that is expected by the monitoring
> station, does this mean that I can have a computer to control a DTMF
> encoder in order to send code sequences to the monitoring station? Is
> there any response from the monitoring station that I need to listen
> to, or I can be in "transmit only" mode? Is there any spec to CID tone
> length, pause between tones, or any other restrictions?
> Thank you.

The answers to all your questions would be yes, yes, yes and yes.

If you're half a computer hardware and software buff you can send CID
signals and even construct a receiver to do so.

The question is would you really want to implement such a concoction in
a real life situation? The liability you'd incur by sending signals to a
CS with such an unreliable homemade setup would hardly be worth any
price saving or knowledge learned.

On the other hand if your only intention is for the learning experience,
everything that you've asked can be achieved on a very low budget.