That is one of the few that can connect to any type of internet. It has the newer ADSL2 also.
You really only need a router that matches your current internet unless you plan on moving or something. You are best off buying a normal ethernet based router if you can they are pretty inexpensive.
They do sorta make a converter but what it really is the part of system that lets people run DSL over their own private phones lines. It is basically a small version of the deivice the phone company has in their office called a DSLAM. It would almost be crazy to even think to do it even if you could afford it. These are the type of devices they do not quote prices on so you know they are expensive.