When Telcos were required to route 800 etc. numbers to the carrier of the called party's choice, [each] 800 call then required a data dip, [and this] was on every call to a toll free number. DEC (remember them?) was the contractor who originally won the bid, but they only promised the usual reliability that was customary in computere installations, but the telcos balked saying that wasn't good enough considering the amount of paying traffic that would be lost in the failed dips. As I recall, the telcos (by then perhaps represtned by BellCore) insisted on a reliability guarantee of something like .9999. I don't recall the outcome.
-- Wes Leatherock snipped-for-privacy@aol.com snipped-for-privacy@yahoo.com