The problem is, DSL providers only support certain modems. The old att modem may not work on your new service. What you have is an actual modem/router combo unit. If you already have a modem then you won't be able to use this model without doing some major setting changes in the setup page. And I'm still not sure it would work. Do you already have a working modem and just want to use the router capability? I would suggest buying a new stand alone router. But usually if you do a hard reset on the linksys router and then hook it up, it should automatically connect and allow internet access.