BladeCenter T and BladeCenter HT units support Network Equipment-Building System (NEBS) mode.
If you are operating a BladeCenter T or BladeCenter HT unit in a NEBS (Telco) environment, you must enable NEBS mode by selecting the Network Equipment-Building System (NEBS) mode check box in the BladeCenter Chassis Configuration Setting section of the Monitors → Power Management page (see Power Management for additional information).
In a NEBS environment, the fans in the BladeCenter unit do not speed up as readily in response to potential thermal events as in a non-NEBS environment. To enable acoustic mode for the BladeCenter unit, which reduces blade server power consumption to stay within acoustic noise limits, you must disable NEBS mode.