D-Link DSL-2790U User Manual page 134

Section 6 - Connecting To Your Wireless Network
3. The Wireless Network Connection box will appear. Enter the
WPA-PSK Wi-Fi password and click Connect.
It may take 20-30 seconds to connect to the wireless network. If
the connection fails, please verify that the WPA-PSK settings are
correct. The Wi-Fi password must be exactly the same as on the
wireless router.
D-Link DSL-2790U Wireless N300 ADSL2+ Modem Router User Manual 129