If you have cable they should be providing any new equipment and setting it up for you -I think??...
have you checked you providers website?

You should only need the special converter box if you use antenna only.

But I never had cable so I'm not sure - Maybe I need to check into it more because my parents have cable.

I know most of what i read mentioned that the cable companies should take care of any changes needed for their customers.

http://www.getreadyfordigitaltv.com/home.htm