D-Link DWA-556 User Manual page 40

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-556 User Manual 40