Right now I'm on a dumbphone with a long out-of-contract family plan (Cingular-era). If mine's the master line or one of the additional lines, I don't recall. Anyway, I'm looking at finally making the jump to a smartphone.
Can I subscribe to an individual data plan for the smartphone and maintain my current voice package? It would be rather inconvenient to have to re-contract three phones (two users who wouldn't want to upgrade any time soon). Not to mention I have no desire to break off onto an individual voice plan and pay $40/mo for one line when I don't use that much voice to begin with.
Can plans be mixed with this or is it an all-or-nothing setup? Oh, one other question: is it possible to receive a new number on phone upgrade or does that count as adding a line? I'd actually like to port my current number elsewhere and get a new one on ATT.
(How have you not added smartphone to your spell check dictionary?)
You should be able to upgrade and keep the same rate plan if it was a cingular plan. If it was one of the pre-cingular (ATT Blue) you would not be able to. If you get a smartphone you will just have to add one of the smartphone data plans to that line. It will not effect any of the other lines.
If your line is no longer in contract then what I would do is first add a new line to your family plan getting the smartphone you want. Once you have it and it's working you can then port your old number to wherever it was you were taking it to.