When setting up a wireless connection, some wireless software will prompt you to enter the router's PIN to set up a secure wireless connection.
You'll find the PIN in the WiFi Protected Settings.
Alternatively, the wireless software may give you a PIN for you to enter onto the router's admin pages - an example of a BlackBerry device has been included below:
In this case, type the key provided by the wireless device into the WiFi Protected Settings:
If you find you're unable to connect using WPS set up, don't worry. Simply connect by entering the router's wireless password instead.