GSM networks

GSM networks are far more popular globally, but in the US, Verizon Wireless, a CDMA network , boasts the highest number of subscribers and broadest coverage in the country. International roaming: In your home market, it doesn’t matter what kind of network it is, with the focus instead on the available coverage.

Which Are GSM? In the US, Verizon, US Cellular, and the old Sprint network (now owned by T-Mobile) used CDMA. AT&T and T-Mobile used GSM . Most of the rest of the world used GSM.

A Global System for Mobile Communication Subscriber Identity Module , or GSM SIM card, is a SIM card that uses the GSM network. Having this card in an unlocked cell phone while using the correct frequency allows a cell phone user to use his cell phone in various countries all over the world.