1. You can swap your SIM card between compatible devices and keep the same phone number.
2. You cannot use a GSM phone without an active SIM card for anything but 911 calls.
3. As long as the device operates w/ the 850 and 1900 mhz frequencies and is unlocked, it should work with At&t.
If you have further questions, don't hesitate to ask.
I want to just start off by apologizing if this either incredibly obvious or if this is the wrong place to post this, but I cannot for the life of my find answers to these questions.
Hello! I'm considering buying an unlocked cell-phone and I have a few questions about them.
1) I currently have at&t and I have a locked galaxy s2 with a sim card. can I use that sim card on an unlocked phone, even though it came from a locked phone?
2) Can an unlocked cell-phone be used without a sim card? From what I have heard, they can be used without the sim card, you just can't do anything that uses 3g/calling/texting/etc...
3) I'm wanting to get an xperia Play unlocked phone, and as far as I can tell they don't have a locked version for at&t. will this have any affect on whether or not the unlocked one will work with at&t?
If anybody has any answers to these questions, I would be grateful if you helped me. Thanks in advance!