Abstract: A security system comprises a host system, a plurality of master controllers and a plurality of sub-controllers, wherein each sub-controller is assigned a specific master controller as well as alternate master controllers for communication access upon failure of the primary master controller. The host, master controller and sub-controllers are all coupled by a series of primary communication networks and paths and have multiple alternative communication network paths which function should there be a failure of the primary communication network. The host system comprises system and application software, data storage devices and communication ports to support the application requirements of the master controller, sub-controller network and access control devices attached thereto necessary to support a fault tolerant network.