ESSX - What does ESSX stand for? The Free Dictionary
References in periodicals archive
What BellSouth is rolling out is ISDN service for ESSX centrex customers in states where ISDN tariffs have been approved.
As far as prices go, BellSouth is saying that the average price for an ESSX 2B+D line will run around $65.
EAch terminal is accessed by local direct-inward-dialing (DID) lines from the state's ESSX