I just found out the company he is getting the DSL internet service from has to arrange with AT&T to use the existing lines, it is called Stand Alone service. This is not available in all areas. The guy he was talking to about the DSL service in as much as said "You don't need anything but a DSL compatible modem and he will take care of the connections". At first he said all we need to do is plug the modem into a telephone wall socket, no wiring required. So much for informed sales people.
By the way, DSL Standalone service jacks will not have a dial tone if you don't have telephone service.
Yes, you do have to pay for the DSL service.