Can I buy a used iPhone to use on an existing AT&T plan w/o data?

[mekkon]

Okay, I've searched but found contradictory info... Now that the iPhone 3G is out, there are loads of old ones for sale pretty reasonably.

I'm currently on a basic family plan with AT&T (with no data), and am thinking about buying a used iPhone to replace my current SonyEricsson. I want the iPhone functionality and Wifi, but don't want to use or pay for EDGE/3G data.

Since I'm already on AT&T, can I just buy a used iPhone, pop in my SIM card and have the iPhone be working fine except for data?

OR - Does it need to be unlocked for me to do that? (I've found posts that say both...) And then if unlocked, I have to avoid software updates with it, right?

Finally, if it does work (either unlocked or locked), will it still try to access the data network and cause me to get billed for data, or is there some way to turn off EDGE data within the phone?

Many thanks

 

[illutionz]

Nowadays the unlock method is so sophisticated that you shouldn't even worry of it breaking.

What you do now is that you install a custom firmware via pwnagetool which also unlocks the baseband and install necessary softwares. When new updates come, there will usually new pwnagetool as well to support it.

 

[TechIsCool]

Here is how to disable Data

 

[ivan1]

does this unlockit program works for the 3g model ??

 

[ec51]

Pop in you sim...call AT&T and add the "WIX BLOCK" it will disable all pay per use data connection (wifi will still work) and you should be all good to go.