Abstract: A security system and method for building complexes having multiple units provides enhanced resistance to intruder disablement, particularly for systems having a unit controller and user input device that are mounted within a common control panel. The system and method are useful with residential building complexes having residential units such as apartments and condominiums, and commercial building complexes having commercial units such as offices, businesses, or storage facilities. A unit controller communicates a unit alarm condition to a main controller located remotely from a respective unit. The unit alarm condition can be communicated via wireless communication. Also, the unit alarm condition is communicated without significant delay following the sensing of a security condition in the unit. For example, the unit controller can communicate the unit alarm condition to the main controller substantially immediately following sensing of the security condition.