Dial or cellular Primary mode can be used when a broadband connection is physically unavailable. In Dial Primary mode, cellular access is used exclusively for transport and there is no associated broadband Ethernet capability.

Dial or cellular Backup allows for continued network connectivity in the event of a broadband outage.

Dial/ISDN/cellular usage may incur additional charges dependent on the type of account used for the connection. 

These features can be enabled in three ways, manually, automatically through the AT&T Administration Server, or a combination of manual and automatic configuration. Much of the configuration parameters are shared between Primary and Backup modes, but there are differences in the way each mode can be set up. These differences are covered in the following sections.