Each 8720 switch runs with two replaceable internal power supply modules that provide all of the power needed for the switch to operate. You can remove one power supply module without interrupting the switch's operation. Supported power supply configurations include two 750 W AC power supply modules, two 750 W DC power supply modules, or one 750 W AC and one 750 W DC power supply module. Power supply modules have integrated cooling fans that operate independently of the switch fans, and are available with front-to-back or back-to-front airflow. The direction of the airflow in both power supply modules must be in the same direction, and must also be the in same direction of the airflow in the fan modules.
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