Apple 17-inch MacBook Pro (User’s Guide) - Manual (Page 54)

54 Chapter 3 Using Your MacBook Pro
Using Multiple USB Devices at the Same Time
You can purchase a USB hub to connect multiple USB devices to your computer.
The USB hub connects to an open USB port on your computer and provides additional
USB ports (usually four or seven). High-speed hubs can support USB 2.0 high-speed
devices as well as USB 1.1 compatible devices. USB 1.1 hubs don’t allow high-speed USB
devices to operate at their maximum data speed. Most USB hubs have a power adapter
and should be plugged into an outlet.
Note: If you are using a chain of USB devices and hubs, some USB devices might not
work when connected through a combination of USB 2.0 high-speed hubs and USB 1.1
full-speed or low-speed hubs. For example, you might not see an external USB hard
disk on your desktop. To avoid this problem, don’t connect USB devices with different
speeds together. Connect your high-speed hub directly to your computer and connect
high-speed devices to it. Connect a full-speed or low-speed hub directly to your
computer and connect similar speed devices to it.