▁Virginia , ▁was ▁one ▁of ▁these , ▁with ▁a ▁foot print ▁between ▁Washington , ▁DC ▁and ▁New ▁York . ▁T D X ▁carried ▁data ▁( anal og ▁mode m ▁up ▁to ▁digital ▁D S 3 ), ▁and ▁built ▁its ▁own ▁tele phone ▁switch es ▁at ▁its ▁engineering ▁facility ▁in ▁Ch ant illy , ▁V A . ▁T D X ▁voice ▁switch es , ▁called ▁" S ST s " ▁( s at ellite ▁switching ▁terminal ) ▁were ▁cent r ally ▁controlled ▁nation wide ▁by ▁Per kin - El mer ▁main frames ▁in ▁F alls ▁Church , ▁and ▁were ▁some ▁of ▁the ▁first ▁long ▁distance ▁switch es ▁to ▁util ize ▁least - cost ▁routing , ▁follow - on ▁account ▁codes ▁and ▁P IN s . ▁For ▁a ▁short ▁time , ▁T D X ▁tout ed ▁a ▁position ▁of ▁being ▁one ▁of ▁the ▁primary ▁prov iders ▁of ▁phone ▁and ▁data ▁service ▁for ▁the ▁World ▁Trade ▁Center . ▁ ▁By ▁ 1 9 8 7 , ▁T D X ▁was ▁rapidly ▁expand ing ▁its ▁le ased ▁fib re ▁network ▁west ward , ▁and ▁by ▁mid - 1 9 8 7 ▁C able ▁and ▁W ire less ▁Communic ations ▁pl c ▁had ▁completed ▁its ▁purchase ▁of ▁the ▁T D X ▁network . ▁For ▁most ▁of ▁the ▁late ▁eight ies , ▁the ▁long - distance ▁company ▁was ▁named ▁C able ▁& ▁W ire less ▁Communic ations , ▁Inc , ▁and ▁the ▁fib re / data ▁business ▁was ▁named ▁C able ▁& ▁W ire less ▁Management ▁Services , ▁Inc