iPhone Unlock is the device that unlocked network to use the sim card of other countries.
For example, the iPhone you buy from the US bring (Only use the US network) to your country, you have to unlock sim card to hear/receive calls.
iPhone Unlock has 3 types:
- iPhone is imported code from Apple to become an international iPhone.
- iPhone is attached Gevey Sim to be able to hear, call.
- Unlocked iPhone with jailbroken software (only works with older models such as iPhone 3GS)
Advantages of iPhone Unlock:
- Use many sims of the network.
- For unlocked iPhone used code then is stable.
- For iPhone Unlock by Gevey sim then price is cheap.
Disadvantages of iPhone Unlock:
- Easy to buy the iPhone built, repaired.
- Except iPhone Unlock by code (expensive price), the other types of stability is not high, software error, or network wave loss. So you should think before you buy iPhone Unlock.
Well almost everyone here have already answered your question, so to be more brief about it, iPhone unlock basically mean that an iPhone is only exclusive to a certain carrier and you cannot use different carriers for it. To unlock it you have to ask the carrier ( where you bought your iPhone ) to unlock it or go to a near apple store.