What are low/high power devices and bus/self powered hubs?
You may connect high power devices to self powered USB hubs only and low power devices to either bus or self powered hubs. High power devices are devices that draw more than 100mA; low power devices are ones that draw 100mA or less. Examples of high power devices are bus-powered cameras and bus powered hubs. Low power devices are typically mice, keyboards, joysticks, and any devices that come with their own power supply (also known as self powered devices). Some general purpose hubs come with their own power supply and therefore are self powered. A subset of hubs called bus powered hubs gets power from the USB bus and therefore has the limitation of only supporting low power devices.
