My parents signed up for Direct TV last fall. They asked and got permission
to have a second box for their RV for use while they travel. No proplem, but
they did have to purchase a second dish. The extra box costs $5 a month.
They were told that hooking up to the phone line only made pay per view
quicker/easier. Since they don't use ppv, their boxes have never been
connected to a phone.
Perhaps things have changed since then.
Scott