Apple iMac (21.5 and 27-inch, Late 2009) - Manual (Page 12)

12 Chapter 1 Ready, Set Up, Go
Step 3: Turn on your wireless keyboard and mouse.
Press the power button on the right side of your Apple Wireless Keyboard, and slide
the switch on the bottom of your Apple Magic Mouse to turn them on and use them
with your iMac.
Your wireless keyboard and mouse come with AA batteries installed, and they’re
already paired with your iMac. Pairing allows them to communicate wirelessly with
your iMac.
When you first turn on your keyboard or mouse, the indicator light glows steadily for 5
seconds, indicating the batteries are good. Then the indicator light blinks until you turn
on your iMac and a connection is established. If your keyboard or mouse don’t turn on,
make sure batteries are installed properly and charged (see page 47).
Note: If you purchased a USB keyboard or a USB mouse, connect the cable to a USB (d )
port on the back of your iMac.
On/off button Indicator light
Indicator light On/off switch