some older alarms do this when doing a walk test but normaly it is the strobe light not the siren ie optima panels try setting the alarm stay in the room with the detector in it keeping still or it will not set and then leave for a few seconds to settle then walk infront ofit as if you are an intruder this should activate the alarm internal and external normally about 20 minuits old standard now 15 mins new standard i am assuming that it is not monitoted by a alarm receiving centre (ARC) and that it is not manitaned and set up for remote or engineer reset.
Chris AXIS Fire & Security, March 2007
