Verizon is one of two national carriers to use CDMA technology; the other national CDMA carrier is Sprint PCS. Another CDMA carrier which is not considered national, but has a large presence in many areas, especially the rural South, is ALLTEL. Three national carriers—AT&T Wireless, Cingular Wireless, and T-Mobile USA—use a North American version of the global GSM standard. The final national carrier, Nextel, uses its own technology known as iDEN, which is derived from TDMA technology.