We had cleaning ladies trigger our alarm and police showed up. Only problem- we never heard the alarm. Is there a siren that we can attach to the system?
The GC3 is a discontinued panel, but it did support a couple Z-wave sirens.
Similar posts about the GC3 and sirens are found below. The first link has some previously confirmed model info and the second link suggests a work-around if the Z-wave siren model used is not immediately sounding on an alarm.