Is AT&T CDMA

Carriers operate under one of two types of networks: CDMA or GSM. Out of the four biggest carriers with their own network, AT&T and T-Mobile run on GSM , while Sprint and Verizon Wireless use CDMA.

Straight Talk supports most GSM and CDMA phones and offers nano, micro, and standard SIM cards for use with a variety of phone models. However, what’s available in your area will depend on the networks available to you.

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 .