How to get a GSM phone to work?

Insert Sim card into Cell PhoneTo get an unlocked GSM phone working, all you need to do is insert the carrier’s SIM card into the phone.

Unlocked GSM Cellular Phones can be used with any Global System for Mobile Communications compatible carrier. In the United States, AT&T and T-Mobile are major GSM compatible carriers. Throughout Europe and most of Asia, all of the major carriers are GSM compatible.