sounds like a pile of poop...
say you house was instantly destroyed by a meteorite, there's nothing left but a smouldering crater in the ground
there has been nothing signalled from the property yet a proper alarm with proper alarm signalling would inform the keyholders that the system has been lost...
The zone circuit from your alarm are positive loop, the sensor has a voltage free relay with series resistor it will measure a certain value dependant on the manufacturer, lets guess at texecom medusa say 18ohms + the value of the cable run circuit will measure 20 ohms
I neither know or care what voltage comes out of the zone of a 700l, however the sensor will have relay which is probably good for up to 50volts, use the sensor to control a relay for the alarm & relay for the HA
Given a big enough bag of relays you should be able to switch just about anything or have massive electrical fire depending on you ability, however you mickey mouse alarm doesn't really have much in the way of input or outputs
Personally I'd choose an intruder alarm controls & HA system which marry up together... something like control4 & texecom will cost thousands