This option determines whether the application operates based on the Hardware Input (BI). If Unit Enable is selected in the Optional Features (VAV-SD) section, then when the Network Input does not have a valid command from the network, it is considered unreliable (and the unit is enabled). If both BI and BV are selected, the state of both must be Enable for the unit to operate (that is, either input can be in a shutdown state to cause the unit to stop).