1) At and t alternative 2) AT&T alternative 3) AT&T competitor 4) ATT rival 5) Baby bell competitor 6) Bell atlantic competitor 7) Big initials in telecom, once 8) Big name in long distance 9) Big name in long-distance 10) Bygone telecom co 11) Call letters 12) CCCLXVII x III 13) Company acquired by Verizon Found on https://www.crosswordclues.com/clue/mci
Media control interface. A multimedia specification designed to provide control of onscreen movies and peripherals like CD-ROM drives. Found on http://www.encyclo.co.uk/local/22285
Multiport Communications Interface. Card on the AGS+ that provides two Ethernet interfaces and up to two synchronous serial interfaces. The MCI processes packets rapidly, without the interframe delays typical of other Ethernet interfaces. Found on https://www.encyclo.co.uk/local/22803