D-Link DWR-921 User Manual page 77

Section 5 - Connecting to a Wireless Network
3. Enter the same encryption key or passphrase (Wi-Fi password) 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 the one on the wireless
router.
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