Peter Clark wrote:

DirecTV's phone connection only sends Pay Per View usage data back to
their computer, it is not used for authorization or activation of the
receiver. One time I had the phone line connected in a spare room,
but accidentally disconnected the run to the multiswitch. When a
guest wanted to use it (god alone knows how long later) I had to call
DTV and have them hit the receiver, even though they showed that the
box dialed in as scheduled.

It sends viewer data back as well. Or earlier versions of it did...

http://www.directv.com/DTVAPP/custom..._phoneline.dsp
"Get the most out of your entertainment experience by keeping your
DIRECTV® Receiver connected to a land-based phone-line.

How does staying connected help you?

It allows you to order pay per view movies and events with your remote
control and avoid phone-order assistance fees. You'll also be able to
order other special programming and products through your on-screen
guide such as Local Channels and DIRECTV — The Guide®.

Your sports subscription packages will be mirrored to the other DIRECTV
Receivers in your house.

You'll be able to upgrade to our advanced receivers such as the DIRECTV®
DVR.

You'll be plugged into our system for future interactive capabilities."

How do they pro-rate? Do they limit the amount of times you can do
this? How about taking 'vacation' 3 weeks a month?

http://www.directv.com/DTVAPP/get_di...tions_cost.dsp
"If you have additional questions, call us toll-free at 1-888-777-2454"

Used to be vacation billing info on the website, quick browse didn't
find anything. I'd suggest the newsgroups specifically for this item, if
you want to continue information gathering in this manner...