What is it?

Sine

does anyone know what this black box is for?  our newly acquired second hand Motorhome has one fitted on the main window in the habitation area and one on each of the garage doors.  it says Truma on the unit but I can't find anything online.  If it's an
alarm then we have no key fob or such like for it and Haven't been able to set it off either!  We asked the dealer but he didn't know either.  Any suggestions?