D-Link DIR-665 User Manual page 71

Secton  - Securty
5. Enter the same security key or passphrase that is on your
router and click Ok.
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-Lnk DIR-665 User Manual 6