MCI Communications

MCI Communications Corporation (originally Microwave Communications, Inc.) was a telecommunications company headquartered in Washington, D.C. that was at one point the second-largest long-distance provider in the United States.

MCI was instrumental in legal and regulatory changes that led to the breakup of the Bell System and introduced competition in the U.S. telephone industry. Its MCI Mail, launched in 1983, was one of the first Email services and its MCI.net was an integral part of the Internet backbone.

The company was acquired by WorldCom (later called MCI Inc.) in 1998. Provided by Wikipedia