Swapping blackberry sim back and forth

[jrbnc]

Hello,

I've seen some posts on the web with people questioning this, but I didnt see a definitive answer, I hope some one can help point me in the right direction. I bought the Iphone and activated through ATT about 4 months back. At that time I tested by taking out a colleagues blackberry sim card and putting it into the iphone, all was well as i called his number and the iphone rang. Internet worked fine, everything worked except visual voicemail, but ok.

So now I transferred my number into my company for corporate responsibility and was issued a Blackberry pearl. So I tried to put my BB sim into the iphone, but it didnt work, iphone said Sim not recognized, and if i turn off then back on, it says i need to activate through itunes. If i put the original sim(inactive one) back in then I get full functionality except for phone obviously, it just says no service.

I guess i have two questions.

1. Why would it work before no problem but not now?

2. Would any of the available tools such as the unlocking ones like anysim, let me use my BB sim card successfully in the iphone without having to do the activation through itunes?

Thanks again for any help!!

Josh