Cingular LLC, headquartered in Atlanta, Georgia, United States, is the largest mobile phone company in the United States, with more than 58.7 million subscribers. The company has the largest digital voice and data network in the United States.
Cingular was formed through mergers and acquisitions, and as a result of these – as well as the rapid technological change in the wireless industry – Cingular operates wireless networks using many different wireless communication standards. The most widely used of these technologies is called Global System for Mobile Communications, or GSM. On top of its GSM network Cingular operates a data network called GPRS (General Packet Radio Service) and an upgrade for faster speeds called EDGE (Enhanced Data rates for GSM Evolution). Cingular supports their legacy TDMA and analog networks; however in March 2006 they announced that these networks would be shut down by February 2008. As part of this effort, Cingular will charge a $5 monthly fee to those customers who still use TDMA phones. Former networks include various paging services and the Cingular Interactive division that became Velocita Wireless which was recently purchased by Sprint Nextel.
Among the services that Cingular aggressively promotes is its “Rollover” service, allowing customers to keep unused minutes from month to month on a twelve-month rolling cycle on its popular “Nation” nationwide plans.