AT&T Mobility LLC (usually braned AT&T, and formerly named Cingular Wireless LLC) is the wholly owned wireless subsidiary of AT&T Inc. AT&T Mobility is the largest mobile phone company in the United States and it also operates in Puerto Rico and the United States Virgin Islands. AT&T Mobility has approximately 71.4 million subscribers as of the first quarter 2008, and operates the largest digital voice and data network in the United States.