AT&T is a leading name in telecommunication industry and it deals in wireless services, cell phones, high-speed internet, digital TV, home phone, DSL, and many other communication services. AT&T Corporate Office Headquarters is in downtown Dallas in Texas. The company is now one of the largest providers of fixed as well as mobile telephony. The company has a customer base of more than 100.7 million customers. AT & T offers many flexible mobile plans and even operates on 4G network and offer U-verse service as well. The company also rolls out high-speed internet service to rural areas to expand its reach. The company also donates a lot of money to political campaigns.