What are SIM cards and how do I unlock my phone?

If you wish to unlock your current phone, please visit: http://www.n1wireless.com/Unlock_Your_Phone_Unlock_Your_Phone.html

An unlocked phone is a phone that can work with any sim card and/or GSM service provider.

Ordinary cell phone service works so that the unique serial number in your phone (its ESN) is used by the cell phone service provider to identify who you are. The wireless service 'knows' that a particular phone's serial number is your phone and knows to send phone calls to that phone when someone dials your phone number.

A GSM phone is not directly linked to you. Instead, it has a removable account card, called a SIM (subscriber information module) and this SIM has a unique serial number on it. This is what identifies you to the wireless provider.

The important difference about this is that you can put your SIM into any compatible phone (and pretty much all modern GSM phones are compatible with all modern SIMs) and that phone will now act as your phone, because the wireless company sees your SIM inside it. It doesn't care that you've changed phones, all it cares is where to find your SIM.

And now for the really exciting part of this. Just as, in theory, you can put any SIM in any phone, the opposite is also true. Any phone can work with any SIM. So, if you've already bought an expensive phone that you like and have learned how to use, if you change from one GSM wireless company to another one, you don't have to change phones. You can keep the phone you've grown to like, and all you need to do is replace the first company's SIM with your new service provider's SIM.

But, some wireless providers 'lock' their phones, meaning that their phones have been programmed to only work with SIMs issued by their company. Reversing that programming - unlocking your phone so it can work with any SIM - is what this is all about.