Abstract: In one implementation, an environmental controller operates a cooling system in an electronic device. The environmental controller includes a closed loop control system for operating a cooling fan at a target speed. The environmental controller may select the target speed based on one or more temperature sensors. The environmental controller may select the target speed based on the speeds of additional fans or the fans may be controlled in unison. The closed loop control system includes a proportional weight. When a measured cooling fan speed deviates from the target speed by more than a threshold error value, the proportional weight is constant. As the measured cooling fan speed approaches the target speed, and the threshold error value is crossed, the proportional weight is variable. The variance may be a function of time such as a periodic stair step function.

Abstract: In one implementation, an environmental controller operates a cooling system in an electronic device. The environmental controller includes a closed loop control system for operating a cooling fan at a target speed. The environmental controller may select the target speed based on one or more temperature sensors. The environmental controller may select the target speed based on the speeds of additional fans or the fans may be controlled in unison. The closed loop control system includes a proportional weight. When a measured cooling fan speed deviates from the target speed by more than a threshold error value, the proportional weight is constant. As the measured cooling fan speed approaches the target speed, and the threshold error value is crossed, the proportional weight is variable. The variance may be a function of time such as a periodic stair step function.

Abstract: A system and method for configuring a slot to be compatible with both modules that are compliant with the isolation requirements for power over Ethernet and modules that are not compliant.

Abstract: A system for selectively forming high-speed serial connections between various components of a network device that includes a multiplexing switch coupled a GE slot and to the high speed serial interfaces of a PHY and at least two network devices. The switch can be programmed to connect the serial interfaces of the two network modules to provide a high-speed, low-latency serial link between the two network modules. Alternatively, the serial interface of a network module can be connected to the GE slot to provide a high-speed, low-latency serial link between the network module and the GE slot.