Digital AMPS
Later, many AMPS networks were partially converted to D-AMPS, often referred to as TDMA (though TDMA is a generic term that applies to many cellular systems). D-AMPS was a digital, 2G standard used mainly by AT&T Mobility and U.S. Cellular in the United States, Rogers Wireless in Canada, Telcel in Mexico, Telecom Italia Mobile (TIM) in Brazil, VimpelCom in Russia, Movilnet in Venezuela, and Cellcom in Israel. In most areas, D-AMPS is no longer offered and has been replaced by more advanced digital wireless networks.
Read more about this topic: Advanced Mobile Phone System