HP Compaq Series Hardware And Software Manual page 146

Hardware Components
USB hubs can be connected to a USB port on the notebook or on
an optional docking device (select models only), or to other USB
devices. Hubs support varying numbers of USB devices and are
used to increase the number of USB devices in the system.
Powered hubs must be connected to external power. Unpowered
hubs must be connected either to a USB port on the notebook or
to a port on a powered hub.
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