50D-Link DAP-1520 User Manual
Section 5 - Connecting a Wireless Client
3.  Enter the same security key or passphrase that is on your router 
and click Connect.
It may take 20-30 seconds to connect to the wireless network. If the 
connection fails, please verify that the security settings are correct. The 
key or passphrase must be exactly the same as on the wireless router.