Using GSM shield to send text messages from a alarm system

I'm pretty confused with the Simple Set reader to be honest. I have a Accenta G4 panel, but the instructions don't show the wiring to that panel only the G3, which I assume is an older system. I asked someone and they said don't use PTS for it because it communicates down the comms line - the same as the remote keypad. What do you think seems as you seem conversant with alarm systems?

Thanks, Dan