Raspberry Pi A User Manual page 42

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can connect the keyboard and mouse directly to these ports. If you're using a Model A, you'll
need to purchase an external USB hub in order to connect two USB devices simultaneously.
Figure 2-3:
The Raspberry Pi
Model B's two
USB ports
A USB hub is a good investment for any Pi user: even if you've got a Model B, you'll use up
both your available ports just connecting your keyboard and mouse, leaving nothing free for
additional devices such as an external optical drive, storage device or joystick. Make sure you
buy a powered USB hub: passive models are cheaper and smaller, but lack the ability to run
current-hungry devices like CD drives and external hard drives.
If you want to reduce the number of power sockets in use, connect the Raspberry Pi's USB
TIP
power lead to your powered USB hub. This way, the Pi can draw its power directly from the hub,
rather than needing its own dedicated power socket and mains adapter. This will only work on
hubs with a power supply capable of providing 700mA to the Pi's USB port—more than will be
available on cheaper hub models—along with whatever power is required by other peripherals.
Connecting the keyboard and mouse is as simple as plugging them into the USB ports, either
directly in the case of a Model B or via a USB hub in the case of a Model A.
P A R T I C O N N E C T I N G T H E B O A R D