A Tribute to System 75

Work In Progress, hoping to acomplish this project by the end of summer 2015 (once I sort out all the photos taken from the iPhone with the hopes the OCR can read through some blurry images.)

AT&T wrote essentially a tell-all book in their 2nd issue of the AT&T Technical Journal in January 1985 about how they designed a phone system where they probably wouldn’t realize in 20 years would be in 90% of the Fortune 500 and be the foundation of the large enterprise telephony for AT&T, later Lucent to now Avaya.

The System 75 was the first true digitally signaled PBX released by AT&T, which in laymans terms, voice and data traveled in bits and encoded through data, not waves of speech through electricity, like how the first century of telephony worked (just check out the Warner vExhibit.) The System 75 was rebadged as the Definity Generic 1 and 3, and was renamed the Definity ECS and became the defacto standard of their PBX offerings by this point through Lucent, the spinoff of AT&T. This same system would  continue through the Avaya spinoff and most of this architecture has been since discontinued or been recoded into their Linux softswitch currently known as Aura (G3r V16 in which is the 16th major revision dating back to the System 75, if I got the version structure straight.)

a picture showing an org chart of how the System 75 PBX's technical infrastructure.

a nice cover showing an org chart of how the System 75 PBX’s technical infrastructure.

I received a Definity CMC/csi PBX from my followers back in early March and thought it would be good timing to see if I could get access to this book. This was around the same time I got up to the NH Telephone Museum in Warner.

Finding this was difficult, since the Internet is mostly biased against telecom, and ebooks would be too cost prohibitive.

Even an eBay search yielded nowhere.

Since I haven’t gone to college, my place at last resort was the New Hampshire State Library, which is open to the public (and its residents.) Because this was a periodical (a fancy grade of a magazine), this is kept in the reference. I finally was able to explicitly be able to take pictures of this book with my iPhone. Over time, I’ll be posting some of the text and pages of this book to add to this vExhibit. I’d like to give my thanks to Rebecca, one of their librarians up there in Concord for assisting me with this research project.

Legal Information: The information posted here is copyrighted by respective holders (which I actually don’t even know who due to all the 1st, 2nd, 3rd and 4th generation Ma Bell spinoffs) and the copyright is not intended to be infringed upon. Such content is for “fair use” within reasons of the US Copyright law, as a use for educational purposes. The Curator/Publisher believes such content doesn’t contain such intellectual property violations and most of the technological hardware and software is now considered outdated and End of Life according to Avaya’s support policies, the company that continued development and support of said system. If you feel the copyright is in violation, and if you’re the holder, please Dial Zero and file a complaint.