There are many cell phones sold in the United States but they are locked which means that the carrier that makes them has to unlock it so that it will work correctly. Some thought that unlocking an iPhone was illegal, but it is not illegal to unlock a personally owned cell phone. The next question may be how do I know if my iPhone is unlocked? There are a couple of simple steps that can allow a user to check to see if the phone is locked or unlocked.
First, turn the iPhone off and then find the SIM cover. You may need to use a small tool like a paper clip to open the SIM cover. Once you get it open, take the SIM card out. Put the SIM card from your carrier into the tray and close it back. Turn the iPhone back on and wait for a full two minutes. This gives the phone time to recognize a different card and get connected to the corresponding cell network. After waiting two minutes or more try to place a call. If you can make and receive calls then the iPhone is unlocked. If you are unable to make a call it is still locked.