D-Link DWA-556 User Manual page 33

Section 4 - Wireless Security
5. Enter the same security key or passphrase that is on your router
and click Connect. You can also connect by pushing the WPS
button on the router.
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.
D-Link DWA-556 User Manual 33