As part of the last post, reminding people to comment here, as opposed to my other site; Gary Sager, from the System 75 development team responded (I’m going to be honest unfairly) about my one line opinion wishing the System 75’s core operating system should’ve been UNIX. I believe he took my words too literally. Because I can’t easily move comments from one WP site to another, here is the original text.

In your web page on Oryx/Pecos for the System 75, you ask “it makes you wonder why was this not UNIX?” I think I am qualified to answer the question, being the architect and principal programmer for the operating system (you will find my name on the BSTJ article). At the time the system was being developed we were using the Intel 286 processor to keep costs down. That chip does not have virtual memory hardware, so I got to spec the hardware to implement that. At the time, UNIX was certainly not up to the real-time requirements of telephony on such hardware. BTW, before I really got into the implementation, I had to pass muster with Ken Thompson. The issue of using UNIX never came up. Perhaps today some form of UNIX might be viable on the more powerful chips available, but UNIX is still not a real-time system. Running UNIX as an application on a real-time system might work.

While I understand the abstract differences, I was talking mostly of it’s self healing nature of Oryx/Pecos and the more friendlier end user interface of the “Definity” line of PBX systems. I know people would quickly come to my defense and know my frustrations and strong opinions of UNIX in general, from a professional user, not a technical engineer. You’re welcome to opine to my defense in the comments – to the people I won’t name! 🙂

Anyways, I’m hoping he enjoyed this site with future loyalty and I always appreciate direct comments from the people behind the subjects in this case the vintage Avaya PBX offerings. It’s becoming rare because if Bell or Grey was still alive, you know they’d probably respond to me too! 😉

As a friendly reminder, there are pages on this site where you can contact me. All non pages enable you to comment with a real time response. The former “Dial Zero” page act’s as it’s Facebook-like wall. As much as it’s clutter to me when I visit others sites, I felt well its like the Wall, hell with it!

I do thank him for reminding me to put the final touches in getting the System 75 papers to be digitized. As some of you know, I had a lousy couple of years which has stalled this project. The finished project is to have the entire article as opposed to some other stuff I posted in the same tribute branch of pages. Please give me some time to complete!


Remembering Avaya: NYS Govt | Albany, New York

Some photos that never were posted (by accident.) They had been uploaded in 2012. I wanted to post these sets on my other portals and wondered where they went.



These phones were tied to an inhouse name called the CAPNET known as the Capital Region Network, at it’s height in the late 1980s, early 1990s using at least 80,000 lines on their private network across Albany, and other Capital Region locations and a branch office of 1740 Broadway in Manhattan, New York City. Every other state office building used other vendors, most notably the Nortel Centrex, the Meridian 1, and Cisco’s UCM line of products. I never knew NYS had been a heavy user of Avaya (and that goes without saying) at their flagship city till a decade ago.

Even more, there is no other network reportedly using this number of non IP-heavy lines in any of it’s thirty three year history of the modern day PBX marketed by Avaya today. A System 75 peaks at 600 to 1,200 lines; a System 85 maxed at 30,000, a 5th release of Definity G3r supported 25,000 lines; and most enterprises would link 75s and a few 85s but not in this scale. Documents via NYS’s IT agency and media reports in the late 1980s claimed then network used fiber and microwave plus the DCS linking protocol to link these ol AT&T PBX systems for transparent dialing across a desk, one of the four smaller buildings in Empire State Plaza, or across the Hudson River to a Troy based office. (Yeah, I’m a New York geek, both the city and upstate, I’ll admit I visited NYS/NYC more as a child/teenager then I did with Boston and Southern New England and as an adult.)

The pictured room above had 8400 sets. So this is the Senate Chambers, where the New York State Senate gathers. The Assembly, in an other wing, doesn’t have Avaya sets per se.

These previously posted pictures shown below is an Aastra telephone, of which I am not sure what they are. I will doubt it’s an intercom and/or basic telephones. They share the same shell as Cisco’s/Selisus VIP series sets.

IMG_1127 IMG_1123

In January of 2017, some of the Large Carrier Cabinets were spotted on their eBay store. And I believe there were lucky bidders. The phone that sat on top of the carriers was a Cisco 6821. We know whose being replaced…

Phone of the Day: Avaya Red 7400 Series Voice Terminal – Macy’s 34th Street

Yours truly was Live from New York yesterday. Put it this way, I saw more Avaya Red sets this time around than Ciscos. A couple Avaya Blues here and there.

I don’t know much of the history of the original Macy’s. Macy’s went under 2 decades ago, and was sequentially boughtout by Federated Department stores that went on a buying spree of regional department stores; then in 2005 made their big buyout of the May Department Store chain of brands. Between the Federated and May buyouts Macy’s was in almost every mid sized city than prior to. Most of the Macy’s around where I live used to be the brands of Jordan Marsh and Filene’s both using/used ROLM CBX switches.

What’s interesting is I’ve been to Jordan Marsh/Macy’s stores and they had resemblance to the flagship 34th Street store, while former Filenes still has resemblance of the pre-Macy’s buyout, but by default all first level stores has that signature all white look. More non telephony related subjects to this store I set foot for the first time on the above link.

Now from what I can tell Macy’s uses an Avaya Red PBX. This one appears to go back in the System 75 days. Now I didn’t see if this thing worked, because in Release 14 (branded as 4.x)  of their enterprise PBX system, they depreciated the 7400s because the four-wire cards carried a lot of legacy code (from what I’ve read on the list serves, just dumping the 7400 DCP drivers gave Avaya some million lines of code removed.)

This particular model I forget, because AT&T made various models in the 10 year period, it may be a 7410 BIS set. Also, just because the 8400s released in the early 1990s, it was not a surprise to still have a part number (known as Comcodes or PECs) – I believe some models of the 7400 were still orderables in the first year of the Avaya spinoff (early 2000-late 2001.) If you were still on the 7400s at that point, Avaya did want you to go to the 6400 series (crap sets.)

More to come throughout the week.


Exclusive: Profile of the Voice of AUDIX!

Welcome to AUDIX. For help at anytime, press star-H. Please enter your extension and pound sign.

Default AUDIX Login prompt

 In today’s special post, in continuing series of the early history of modern day Avaya PBX systems, you humble curator had actually reached out to the “Voice of Voicemail”, Lorraine Nelson. I would like to thank her for her cooperation with the project.

Continue reading

Video: Local AT&T Ad for Colorado – 1987

“One company in Colorado designs and produces some of the world’s most sophisticated telecommunications  equipment. That company spends more than hundred million dollars for goods and services with nearly 2,700 local suppliers. And that company helps support local charities and the arts with over a million dollars and 1,500 volunteers.

That company is AT&T. At Home in Colorado.”

att westminster ad

As many the Avaya Red geeks out there would know the Westminster, Colorado facility was where most of the enterprise systems for AT&T, later Lucent then Avaya (including products such as the System 75, Definity, etc) was developed, produced and served locations for technical support (remember the Definity Helpline?)

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Within a couple years after Divestiture, AT&T had tried to refine their brand such as the the infamous tagline “The right choice”. This commercial taken from a newscast from KCNC-TV in Denver (not to far away from Westminster) apparently was designed for the Colorado market, focusing on their local suppliers and returning their favor to non profits, featuring children at the Denver Children’s Museum with kids playing with old sets, and a girl playing with a 7405 or 7434 set.

att westminster ad 3

Years have gone by, and Westminster is like many other high tech facilities in America. Abandoned and ether outsourced or off shored development to people who had no knowledge of the systems from its early years. Sadly the old AT&T legacy is going further into earth than say the other legacy IS systems and equipment. I don’t see the same outrage with actions like startups such as Emetrotel or even VMS Software (yes the same VMS as in Open VMS hiring local DEC coders basically from retirement to continue to develop that operating system!) No, it’s a slow death for Avaya Red. Westminster does still exist, and Avaya is still there, just it’s not all centralized like it once did.

This is one of the unique AT&T commercials of that time.



AT&T Technical Journal Jan 1985/System 75 Tell All, Carrier Switches




In 1984, AT&T started to market their new digital (fully digital that is) PBX called the System 75. The System 75 was a fully new system that could handle infinite technologies such as ISDN, PRI, T-1, and later IP and packet switching. AT&T also marketed the System 85, which was a Band-Aid code version of the Dimension. The System 85 ran on whatever stored software that used for the Dimension, but it shared hardware compatibilities with the System 75. In fact the System 85 had some interesting features such as AUDIX “Unified Messaging”, ports could max out to over 30,000 extensions and support up to 40 attendant consoles. Well, not the 302 console I posted earlier, but a boxy one that was used for the Dimension.

Another system called the System 25 was based almost entirely on the Merlin system with the code, and features. The System 25 is much comparable to a Merlin Magix or Legend system of today, which eventually replaced this odd setup.

What was common with all the cards and the type of carriers is the boards were cross compatible and hardware for phone lines and trunks could be interchanged during a cutover to a larger system. There was a reason why there was color coded labels on the boards, back in those days System x5 systems required tone clocks, processors and auxiliary connections  to be together, line cards and those alike could be free floating if the customer chose so. Later versions of the Definity system would not have color coded labels and the cards could go in whatever fashion.

system75 8


This cabinet can weigh as much as a stainless steel refrigerator, about an 800 pound voice gorilla and can support up to 700 lines.

It’s kinda strange how the power unit is located right next to the processor and tape unit…wouldn’t that cause problems?

To the left and right of each shelf  has a power supply, for each row, it uses two sources of power. What’s interesting in this first version they all have power on and off (or kill switches.)  Newer versions had power in only.

The bottom area was changed to support battery backups, the power supply and it’s tone generator in later years of the Definity/MultiVantage/Communication Manager systems.

It’s safe to say the System 75 scaled horrifically in the beginning again with that 700 port limit. However with creative integrators, you could theoretically have thousands of extensions using multiple System 75 (or even 85) PBXes and link the systems with a Distributed Communications System which would allow feature transparency through multiple of mediums (microwave, fiber, copper, CO, etc.) The New York State Government was a classic example where their Albany network had about 80,000 or so ports/extensions/lines and this was their original setup when commissioning this type of systems in the late 80s, according to Network World. DCS gets lot of mentions in this tell all as this would be a selling point to sell this system to other customers.

AT&T Technical Journal Jan 1985/System 75 Tell All, Attendant Console



Some things don’t change. Sometimes familiarity you shouldn’t mess around with.

In this case, the operator switchboard or Attendant Console as remained mostly the same since 1984, first released for the System 75 PBX. This model # was 302 series, but rarely is branded as such, only in the administrative terminal sessions to add stations and alike. There were 4 different series of 302s, suffixed with letters

A was the model shown below, very Merlin looking, and used button caps similar to Nortels, but more smaller.

B had a different display, with a white instead of metallic.

C replaced the button caps and supported 2 wiring environments. Prior to 302C, you needed the full 8 wires of copper to connect the console. C also introduced modular connections for the hand or headset. Prior to C, the console automatically logged in operators if they plugged in that dual 1/4″ jack into the console. Because of the change of jacks, the operator would had to press a few buttons to log them in.

302D was introduced around the turn of the century and required 2 wire environments only. 302C could work in ether/or environment


At some point, as of this writing in 2015, the 302 Series is officially dead and is no longer sold as new by Avaya as many operators have evolved to administrative assistants doing multiple things and split the calls between those groups, or in some operator environments have been replaced by s0ftware based sets. Operator sets don’t come cheap, and including its Direct Extension Selection or DXS can cost about $1,100 new!

The DXS has evolved, but the  general idea hasn’t changed. In fact the Merlin looking industrial designed remained in tact right to the EOS. The first generation had 8 buttons on the very bottom acting as “Hundreds groups select”. Simply put, if you have dial plan from 4000 to 6000, the bottom 8 buttons would be labeled “40”, “41”, “42” and “53”, “54”. etc. So if you want to call extension 5138, you would hit the bottom “51” key from hundreds group, then  press “38” in the 100 array keys. You can monitor a group of hundreds at a time and in later models as the System 75 evolved from supporting a few hundred extension into the behemoth of the Definity PBX supporting tens of thousands of lines, the Hundreds group keys maxed to 20, so you could monitor a couple thousands of lines if you had that model.




This picture is interesting because its very rare for any AT&T/Avaya Red publication to show exploded views of any of their equipment. This was standard operating procedure for Nortel if someone wanted to replace a part in a console or a set, however it was the job of AT&T to Lucent to Avaya to let this type of work be done by them or vendors.

AT&T Technical Journal Jan 1985/System 75 Tell All, Wiring Panel





This is one of the figure pictures in the AT&T Technical Journal, and the tell all of the System 75 PBX. What’s interesting about the wiring is modular, I’m not sure if the RJ45 jacks come from Amphenol to the cross connect or the voice drops.  I thought most System 75 setups in those days (and probably in the mid 90s) were 66 blocks where you’d take an Amphenol from the PBX and ether splice the wires to a 66 block or plug in it if the block had a female Amp adaptor.

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New Virtual Exhibit – A System 75 PBX Article

I’ve been lucky to obtain access and finally got to the Holy Grail of modern office telephony – that Avaya’s marketing department would never want you to know! We like to focus on other systems, and platforms like the ESS for an example, but what me interested in phone systems in general was the AT&T era of the 1980s.

Thanks to the N.H. State Library, and Rebecca, one of the reference librarians, I got access to the book taking a recent trip to Concord and got nearly 100 pages worth! AT&T at the time which sold the System 75 (later named the Definity ECS, MultiVantage, Communication Manager to Aura, marketed by Lucent and Avaya over the years) did an entire tell-all of how they developed the system, how they developed it, the hardware background, the software background and how they ate their own dog food, as some AT&T sites were the first test groups. Developing the System 75 from concept to market took about 3 years and was on the market by the time of the publication in January 1985.

Despite the 30 year old publication, the kernel and hardware architecture basically remained the same and such architecture helped its way through newer technologies such as ISDN, packet and IP switching and later Voice over IP. It was this concept and system that would have descending companies tout 90% of the Fortune 500 wither company wide or a few locations using this type of communications using the System 75/Definity/CM/Aura platform. It wasn’t really until the last decade did such entity (Avaya) tout such customer base, which probably has eroded significantly under companies like Microsoft and Cisco with their “unified communications offerings”

I’ll be posting this little by little over the course of the next couple of months, with my own take. It’s surprising it wasn’t a form of a white paper or publicized elsewhere, it’s a great read and it’s a rare find, my job is to make it easy for the people who would be so interested in reading this.

Stay Tuned!