An unlocked phone is a GSM phone that is not tied down to any one carrier. So what does this mean? Unlocking a GSM phone enables you to use your phone with any GSM provider anywhere in the world. You simply insert the SIM card into the phone for fast and easy service.

GSM is one type of digital technology and is not compatible with CDMA, TDMA or iDEN. A SIM card (subscriber identity module) is a removable account card and has a serial number unique to it that identifies you to the wireless provider. A GSM phone is not directly linked to anyone. This means that you can put your SIM into any compatible phone and that phone will now act as yours. It identifies to your SIM not your phone. So now you can simply switch providers without switching phones unless the provider has their phones programmed or “locked” to work only with SIM’s issued by their company.

In the United States, you can use an unlocked phone with the current GSM wireless providers such as T-Mobile, AT&T, SunCom, Cincinnati Bell and if you live in Wyoming, Union Wieless. If you travel abroad, you can swap out your SIM card for a foreign one.

It is a relatively easy process to get service for an unlocked phone. First order and sign up for service either at a T-Mobile or AT&T store or on the carrier’s Web site. After you have your SIM card it is relatively simple, just place it in the phone and start making calls.