MCI

In computing, US-based long distance telecommunications company, active in Net communications since the 1980s, when it ran the backbone for the National Science Foundation's NSFnet.

In 1997 MCI was acquired by rival telecommunications company WorldCom, the new company being known as MCI WorldCom. In October 1999 MCI WorldCom acquired Sprint, the third-largest carrier of long distance calls in the USA. In 2006 WorldCom was acquired by Verizon Communications.