D-Link DSL-2750U Technical Support Setup Procedure page 14

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Step 4: Check the box "Enable USB Modem"
Enter the APN of your 3G service provider, username, password and dial number, if any (pls check the
setting with your service provider if you are not sure).
Click "Apply/Save".
Step 5: Wait for the "modem status" to show "CONNECTED"
CAUTION: Do NOT click on the "Manual Dial" button. Clicking on "Manual Dial" button will force
the 3G connection to become the primary internet connection, and WAN failover function will NOT
work!
FAQ : How To Configure 3G WAN Fail Over