gsm auto alarms

Can anyone give me the pros & cons of car alarms that use a GSM phone for security. Where you can call the car, & turn off the engine/fuel line. Or you can call the car & hear the conversations of whoever is in the car.   pelshakt@gmail.com Thank youMr. Pelshak

Which systems have you been looking at so far?

I think the autopage C3 does this without the listening in.  Careful with GSM, it's a European system and only used by AT&T and T Mobile in the US.  Also it runs on 800 and 1900 whereas the Euro Version runs 900 and 1800, hence all my phones are quad+ bands!  In actual fact though no one in the industry will admit it, the US system as used by Verizon et al is probably better.  By the way, did you mean GPS ?

hey what is the differnce between gps,gsm, i know what gps is but gsm i dont, ive seen the sellers from china selling gsm tacking devices, i contacted them for info, but never got a reply, my question to them was if their tracking system will work on our communiction system. any advice thanks in advance.rocker

GSM is the mobile platform widely used in most of the world except the US. The ranges are 800, 900, 1800, 1900. For the novic, If your phone has/requires a SIM card it is more than likly a GSM phone. If it does not then its whats considered a CDMA, or "fixed wireless". Howie II is correct about the frequency. You can Google to see what frequency are for any particular country.Mr. Pelshak

I have looked at so many systems, over the past 2 years, but I have not found anyone in the US that has used a GSM system that could give me some pros & cons.Mr. Pelshak