Well it seems that some people are too good to answer questions that have been discussed before even though someone is new..... (i mean seriously, you took the time post, just answer his question).
I'll answer. It pretty much depends on what reciever you have. If you have a 322 or 522, then yes you do need a phone line, otherwise you will incur an aditional $5 fee / month / reciever that isn't connected to a phone line.
If you have one of the other recievers, then most likely no, you won't need a phone line.