Access Control 16
Access Control 16 : Physical security: (6) Access control system topologies: Access control System Using Serial Controllers: (2) Serial Main and Sub-Controllers: Disadvantages: (a) Operation of the system is highly dependent on main controllers. In case one of the main controllers fails, events from its sub-controllers are not retrieved and functions that require interaction between sub controllers (i. e. anti-passback) stop working. (b) Some models of sub-controllers (usually lower cost) have no memory and processing power to make access decisions independently. If the main controller fails, sub-controllers change to degraded mode in which doors are either completely locked or unlocked and no events are recorded. Such sub-controllers should be avoided or used only in areas that do not require high security. (c) Main controllers tend to be expensive, therefore such topology is not very well suited for systems with multiple remote locations that have only a few doors. (d) All other RS-485-related disadvantages listed in the first paragraph apply
No records Found