ZZ from MitBBS

 

That's a long story. refer to this link for a complate time line.

Basically

Pa ATT was forced to split into 8 children, 7 RBOC (regional Bell Operation
Company) and 1 long distance in 1984. ATT Long Distance inherits its name

Ameritech
Bell Atlantic
BellSouth
NYNEX
Pacific Telesis (Pac Bell)
Southwestern Bell (SBC)
US West
ATT Long Distance (ATT)

then...

Bell Atlantic ate NYNEX
SBC ate Ameritech
SBC ate Pac Bell
Qwest (an independent fiber optic company) ate US West
Bell Atlantic merge with GTE (another independent company) to form Verizon
Cingular is a JV from SBC and Bell South

from the ATT Long Distance side

ATT spins off Lucent, which was its Bell Lab
ATT Spins off ATT Broadband, which was acquired by Comcast
ATT spins off ATT wireless, which was acquired by SBC
ATT itself was acquired by SBC

then

SBC changes its own name to ATT

The NEW ATT merge with BellSouth
since Cingular itself is a child of both, there's nothing to change.

Verizon ate MCI

Now the original ATT becomes

Verizon, ATT (i.e. SBC) and Qwest (a minnow). The former 2 are more powerful
 as they ate small companies along the way. Once this two decide to merge,
the re-forging of ATT will be complete.