Problem Description:

USB modem is used with the gateway for two main purposes:

1.Dial-in for Services/Management operations. This action can be done by either connecting the USB modem directly to the gateway or connecting the USB modem to the S8300 installed in the gateway.

2.Dial-out for backup interface (Routing interface).

Please see complete PSN document for resolution and additional information.
PSN2475u.pdf