D-Link DWA-120 User Manual page 38

Section 4 - Wireless Security
3. The Wireless Network Connection box will appear. Enter the WEP
key 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 or
access point.
D-Link DWA-120 User Manual 38