Hi,

we've got 2 WANs connected to the Vigor 3900 (2 x ADSL lines) in load balance mode. We'd like to also use a 3G modem as a last resort failover plan when both the 2 WANs fail totally.
Is it possible to setup the router so that the 2 WANs are in load balance mode and if both of the are down the 3G USB modem takes over? If so, then how? Thanks.

isn't there a tick box after you set the 3g as BACKUP and you then tick both WAN1 and WAN2?