I proudly admit I am an AT&T brat. I was born 3 years after the Divesture, so my bias is strong since I never witnessed the old monopoly. Everyone in my crazy life knows how I live and pray upon any of the equipment coming from the old AT&T and its zillions of spinoffs since.
I’d still give these systems a strong plug even when Avaya has essentially taxed companies with excessive License and Right to Use dues, as Cisco has been known to do. If you can afford it, its the best. It’s the Rolls Royce of phone systems.
In the late 80s (just probably before 1990, when they renamed their systems), AT&T ran an ad campaign actually running commericals of their enterprise PBX systems, known at the time Systems 75 and System 85. (System 25 was built upon the Merlin code so its ilrelevent for that reference.) The System 85 was built upon code from the Dimension PBX that was made by Western Electric, and was distributed by the Ma Bell’s operating companies for businesses to lease. The System 75 was based on fully on digital telephony, the ability to use ISDN, the ability to interoperate computer mainframes and run cables on the same line as the dummy terminals. The System 75’s code and its hardware would lead into the 90s and into the last and present decade, with its 16th revision known as Avaya Aura V.6.
In this commercial a train goes into the air, as the announcer says mentions how a communications system “can expand and expand” and ends with
“A new communications system so advance, its litterly impossible to outgrow.”
The Definity name is a contraction of “Definitive Solutions for an Infinite Amount of Possibilities” that Lucent touted in the late 90s on their respected product page.
However after the spinoff from Lucent’s Enterprise Networks division, that became of Avaya, they ruined the name by calling the newer versions of the Definity system after Release 10 “Communication Manager” to “Aura” (which I still am not sure how to pronounce) and maybe in a few years will be another odd name, as Avaya slowly became a modernist, fancy, over stylish company.