blocking data usage

[jbv1987]

i recently bought an iphone. i don't have the $30 plan with at&t. my phone keeps sending data and so i want to call at&t and block my data usage. but will that keep me from sending and receiving text messages?

[djwindsor]

How were you able to activate an iPhone without a data plan? Did you activate a standard phone and just swap out the sim card? I am not certain, but I think they can still determine that you're using a smartphone when you swap out the sim cards. The reason I say this is that when I upgraded from the original iPhone to the 3G i had bought the iPhone 3G from a guy on Craig's list. I swapped out sims and ATT knew I had the 3G handset. I was eating data, but how did they know that the phone was an iPhone 3G?