The 2700 model has a usb port that can be used with a 3G dongle for connectivity and/or fallback. The FireBrick 2500 does not have a USB port
) By using a 3G dongle with 1 or more FTTC/ADSL lines from AAISP you'll be able to fall back to using 3G in the case of the FTTC/ADSL going down - this includes routing of your public IP blocks and IPv6 blocks (IPv6 via a tunnel)
Dongles do vary, and drivers may need to be written to support a particular dongle.
(contact us if you have one which is not working. ) The following dongles are known to work on a FireBrick 2700:
*[[Zoom_USB_dongle|ZOOM model 4598]] (Available from AAISP)
*Huawei E353 (Three branding)