Confused about Network

I have had 3 high speed connections, 1 cable 2 DSL. I tried to network 4 computers at home when I had cable my router work fine with all four comps but my DSL wont work with routers only hubs or switches. Is it possible to make the DSL work with the router. Im guessing its something with the ISP that wont let ya do it. Im currently with Bellsouth DSL right now

The Router /Switch has to support PPPoE (Point to Point Protocol over Ethernet)which is a form of the PPP protocol. The PPPoE provides the authenication information which is required by the ISP to log in to the network. Stuff like: User name, password...usually those things are setup in the router settings.