atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems curious about 1A2

The 1A2 systems are before my time, however I own a model 464 and a 564 phone. I keep and collect some of the old stuff I run across. I recently have been thinking about this stuff more (thanks to the posts by rotary500 and the responses by Ed and Bill). I am pretty sure I own a power supply unit that was used for this (it has 24vdc and multiple 10vac outputs on it with flat bakelite fuses). I have never seen the actual KSU though. Just wonder if someone has found a picture on the net (I did a search, but didn't find any pics of the "shoebox"). Also what is the difference between 1A1 and 1A2? If I found a KSU, would the two phones that I own be compatible or were there differences other than the physical looks?

1A1 was an insane bank of relays that covered a 4x8 sheet of plywood for a couple dozen lines.

1A2 used shoebox ksus and 13 slot panels with an interrupter. Much more compact.

Take a look at these sites. Just call me the google maven.

https://209.165.152.119/tel/1a2.html

https://www.ntcp.com/default.html?target=dept_461.html&lang=en-us

Twisted Pair ----

1A2 old? I'm pulling out a 584 panel with ten button sets this weekend. In a floral shop. Want a picture? I'll take a poloriod and pdf it to you, if you want.

1A1 used co power to pull relays to operate hold, etc. 1A2 had power supplies to do it and have lights. Never played with a 464 but have installed literally truck loads of 564 before TT came to town. Then I put in many 2564s. The shoebox you hear about is normally considered an WECO 551 series or an ITT 601. They are both the size of a shoe box, therefore the name. Normally 4 COs and a chance at a ICM.

Let me know if you want that pic.

KLD

The 1A2's I used to install were on 19 inch free standing racks made by Northern Electric (now beter know as Nortel). You could do an entire floor of a building with several businesses on one rack. Just plug in the number of CO cards you need, the intercom paths, power supply, hold relays you need and assorted perriferals, hard wire them to the proper sets.

When they pull the last of all the copper KSUs and replace them with fiber optic VoIP...it would not surprise me if the cut-order phone call was made over a 1A2 6-button set. <snicker>

In all seriousness, they were built like a rock. Pulled one years ago that had been in service at least thirty years with non-solid state 400E line cards - just current sensing relays.

There are a couple of Qwest CO's here that still have and use 1A2 systems in there buildings. I even worked on one since the "young" techs couldn't fix it.

Yeah, those things are like rocks. We have a customer that had one installed litteraly 30 years ago and had NEVER had a service call until last month! Weird and amazing at the same time.....just try and get a customer like that to update to a new system! LOL

Steve

I've been doing a lot of reading here, Bunnie's link and the old posts on this forum. What was the interrupter used for? Was it part of the KSU or a separate device?

It's an internal part of the KSU. The interrupter is a motor-driven lamp flasher. It has cams inside that close various sets of contacts at different rates per second. One was 60 IPM for incoming call flash, 120 IPM (wink) for hold flash, and then another set of contacts that closed one second on, four seconds off for ringing voltage. It is housed in a clear plastic case and plugs into a dedicated connector in the KSU or card rack. Later on, solid state interrupters were developed, but never became as popular as the motorized ones since they lasted almost forever!

From what I've been reading, if you wire the y/s directly to the co line, it will cause the set to ring. Why did the interrupter have a cam for ringing?