There is no need for phone lines. The rx's work just fine without them. DTV uses the phone line to collect data on what the cx is watching and for how long. They probably sell that info to nielson or something. But otherwise, it has no use. Rx' update software through the sat, and ppv can be purchased over the phone.
This is CABL.com posting #280757. Tiny Link: cabl.co/mblcv