D-Link DWR-512 User Manual page 75

Section 4 - Connecting to a Wireless Network
3. The Wireless Network Connection box will appear. Enter the same WEP
key 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 WEP settings are correct. The WEP key must be
exactly the same as on the wireless router.
D-Link DWR-512 User Manual 70