cool, usual thing of cable, device or controls
if the cable is laid under the boards in a manner its trapped or damaged by a pipe, walking around on the floor above it may send the alarm batshit,
something drawing lots of current, eg too much stuff on small controls may send the alarm batshit
something odd is happening , check all the fuses are the correct rating eg-
some mong may have a 5amp fuse where a 1amp belongs & when it draws too much current it batshits the alarm & does not blown the fuse
with the tamper tied down gently press parts of the endstation pcb to see if it goes batshit
check both continuity of all the all cables & then take them apart & check there is no shorts on every pair ?
or change you mobile no. & find a new friend with a working alarm ?