A building management system enables error-free operation of utility devices in the building by limiting an operator's access to controls for the utility devices to those devices that the operator is authorized to control. The system includes a terminal unit and a central station. The operator inputs various commands via the terminal unit, and the central station verifies that the operator entering the commands is authorized to control the devices designated by the commands before performing the input operation command. The system also verifies that the input operation command is a correct command.
