Auto USB Backup WAN

[Payam Nab]

I just noticed "Auto USB Backup WAN" in Dual Wan section :

When I enable it and click apply it just reboot and enable dual wan.

If I turn on the "Enable Dual Wan" it does the same,
So what's the difference between "Auto USB Backup WAN" and "Enable Dual Wan"?

 

[Pocah]

It's just a handy default. The default is yes, so if the main WAN fails and it detects there is a USB modem there it will automatically set all the settings for fail-over, activate the modem and switch to it. All without you having to do anything.
Course, if you don't want that, then you can set it to no and set it up manually.