Telecom Co. is a term used to refer to companies that provide telecommunications services, such as telephone and internet services. Two of the most well-known telecom companies are NYNEX and ATT. NYNEX is a telecommunications company based in the United States that was founded in 1983 and is now part of Verizon Communications. ATT is an American multinational conglomerate holding company headquartered in Dallas, Texas, and is one of the world's largest telecommunications companies.