How do I fix the fault on my burglar alarm?

We have just moved into a house with an Optima XM burglar alarm.

The internal (panel) alarm goes off intermittently and all the lights on the panel flash on (Zones 1-4, Attack, Tamper and Day). The alarm then stops on it's own.


Normally only the Power light is lit and keying in the alarm code or pressing the reset doesn't seem to do anything.

Do you have any advice please?