Originally Posted by jaegermaster
I swapped my sim card into my wife's T-Mobile Blackberry and it said "invalid sim card" Is there something I am supposed to do after swapping it? Maybe T-Mobile and AT&T aren't compatible?
Still looking for a used AT&T Blackberry.
Ya, typically phones are SIM locked to the original carrier. When you see a phone for sale that says unlocked, then that phone can accept a SIM from most any carrier.
TMO and ATnT both use the same technology, GSM. So devices can work on either network. In your case, your wife's Blackberry is SIM locked and rejecting the ATnT SIM. You would need to get her phone unlocked. You can do this via the carrier or sometimes on the open market.
Your phone will NOT work on Verizon as they use a different technology (CDMA) from TMO and ATnT (for that matter, most of the world is GSM).
I saw the Jailbroken comment too. That is a specific term to iPhones. You just need to unlock the phone you want and it will work with most any GSM carrier. You can have an unlocked iPhone that is not jailbroken.