If you are using DSL lines, you need a modem with an Ethernet Interface instead of a USB interface..
There are quite a few available on the market.
------------------------------------------------------------------------------
Zoom X6 5590 DSL Modem (55900000) 79$ - 95$
DSL Modem, External Enclosure, Ethernet Interface, 24 Mbps
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
Zoom 5510B DSL Modem (55100000B) 36$
DSL Modem, External Enclosure, USB Interface, 8 Mbps
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
Zoom 5615 DSL Modem (56150200) 46$ - 55$
DSL Modem, External Enclosure, Ethernet Interface, 24 Mbps
-------------------------------------------------------------------------------
__________________ |