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?

The yellow slate was connected to B1/R1 leads from the CO line card out of the KSU . EV do you remember working on diode matrix problems with an office full of 20 button sets ? What a nightmare sometimes .

How about setting up multiple button&buzzer keys on a 20/30 button set .You could spend all day just modifying 10 sets .

Twisted:

Yes, if you wanted a single CO line to ring on a 1A2 station, they you could wire that line directly to the yellow-slate pair of the station cable. But, if you wanted multiple lines to ring at the same set, you had to use the internally-generated ring cycle and voltage. This is because if you tied multiple CO lines to the same ringer, they would be effectively tied together.

Internal ringing also created the flexibility to have various combinations of lines ringing at different stations by using a diode matrix to isolate common ringing for some stations. For example, three lawyers all had their own two lines that rang at their station, but their common receptionist had all six lines set up to ring on that station.

Oh, yes OBTW. I remember many sites like you mentioned. We used to service the Kennedy Center in Washington DC that had hundreds of lines, even more stations and lots of mixed ringing. They had lines coming from cards in multiple closets backfed over house cable, lamp extenders, you name it.

It really got fun when there were transfer keys involved. As if the matrix wasn't already confusing enough!

Yes I worked on the 1a2 at RCA records buildging in Hollywood in the mid 70's. The entire building was 6btn to 30btn keysets . The floor that the lawery's were on was the worst . We would draw names to see who would take the service call or move the phones around . Finally it was just mine and one other tech names in the hat .

You mentioned a transfer key Ed. This was possible on the 1A2 system? Could you actually intercom (dial) directly to another extension? From what I have been reading, you installed buzzers in the phones for intercom but was it private 2-way?

Sure, there were multi-path intercom systems available. The AT&T/Western Electric 6A intercom was huge (as in size; all 23" rack-mounted relays that got bigger by the number of stations) but it still only had two paths. The first was a common path shared by everyone, but once a call was dialed, the parties were shifted to a second private path. Once the private path was in use, the next intercom call was on the public path. A third call attempt became a party line.

This was also when people actually got up from their desks every once in a while as opposed to today! If the intercom paths were busy, people just got up and went to the person they were trying to call!

AT&T/Western Electric came out with an advanced intercom system that was similar to a small PBX that was called "Dialog". It had many talk paths and functioned much like a PBX with built-in lamp flash rates for the 1A2 sets, etc. It even had clear plastic overlays for the faceplates on the phones to provide feature dialing codes. It was pretty sophisticated for it's time. Maybe that's why it didn't last very long.

Tone Commander also came out with the Multi-link intercom system for 1A2 called the ML-8000. With the proper cards, I seem to recall that it could go up to 8 talk paths. It also functioned much like a PBX. All intercom call paths were private. Ringback and busy tones were provided when making calls (this was an option). Once the equipped path capacity was reached, the next call attempt resulted in a busy signal when going off-hook. These things were VERY popular in the DC area through the 1980's.

Both of these systems provided "real" ringing or signaling (repeated) as opposed to the single buzz with earlier intercom systems.

Melco and Valcom had multi-path systems as well, although not quite as sophisticated.

Transfer keys were more for ringing on CO lines. Say for example an executive was going out to lunch, he could turn on his transfer key (a side car toggle switch) and his private line would then ring at the receptionist.

EV, This is a little off subject but did you ever work on the Tele Resources 32 "PBX" ? It came out in the mid 70's and was discontinued by 1981 .

Nope. Never touched PBX's until Mitel SX100/200 in the mid 1980's. All I ever worked on was 1A2, Comkey and electronic key until digital hybrids became the norm.

The analog sx100/200 Mitel's were a rock solid pbx as long as you had enough dtmf receivers and the power supplies did not over heat . I started on the NEC Crossbar 60/120 pbx's .

I still have sx-100 & 200's out there on Nantucket

I think there is still alot around in small motel's . I came across a sx100/200 programming overlay in my garage the other day , along with a tech quick reference handbook . I guess I will keep them .

Speaking about relics, I started on the Vantage system. Was that popular south or was that just a Canadian thing? I never hear anyone talk about them on here even though I still have a few customers using them.

Twisted Pair.....
You for got to add a BLF and a speed dialer for that "new" system.

Oh, how quickly a topic changes! I thought this was about 1A2?

I blame OBTW for getting off topic!! lol, sorry.

In my searches of the phones that I have, I found a 565 set. I have the 564, next trivia question: what was the difference?

Any one that knows the 1A2 better than EV must be older than Mr. Bell himself!

We had 1A Key and 10A1 Key then with line cards called 102 Before 1A key we had something called multi key.

it should be 10A2 not 102

what is a 464? are you talking about a line card, cabinet, i don't remember that one.

BTW, ml8000s were extremely popular in the usaf

Okay, you young wippersnappers! Move over or I'll hit you with my cane !!!

564 had common grounds for lamps 565 had a lead for every function.

More trivia ---- Twisted Pair, how do you get a ten button set to operate off of a 25 pair cable when it takes three pair for each C O button?

KLD

KLD- I tried explaining the 10 button set on 25 pairs to my younger techs...damn near scared them into a new line of work.

Heh? Wat'd ya say?

Man, Ken, we are aging by the minute! The 564/2564's made by ITT stayed with common grounds on lamps all the way to their end even though the Bell companies ditched them for 565/2565's across the board to standardize years earlier.

Really, the only reason for the 565/2565 was to incorporate the modified dial and the extra line cord conductors to support the 4A speakerphone. I think the only reason they separated the grounds on the 565/2565 was just a "why not make use of the extra pairs and stop paying for blown fuses on lamp reversals at the same time"! The 565/2565 had an 18 pair (yes, the yellow/blue and yellow/green pairs were skipped) line cord while the station cables were 25 pair. It didn't make any sense to come up with a 21 pair cable to accommodate the speakerphone, so they went with the obvious solution. I sure used a lot of those violet pairs!

You might be older'n me, but you ain't gonna outwit me on this'un!

By the way, I'll bet that 1A2 you are taking out was on that wall a whole lot longer than anything that replaces it will be! Agree? Shhh: Don't answer in front of the customer.

Now, let's go hit the front porch and take another nap...............


:sleep: :sleep:

txfoneman, this is a pic of the 464 set.


Just a guess, a ten button set only requires pairs for 9 buttons, one being a hold. From what I read; the A control is common grounded with the w/o, you just told me it is possible to have a common on the lights, is this where they are getting the extra conductors to run a 10 button on 25 pair?

Signed; young wippersnapper! :shrug:

By the way KLD,

I hope you are taking a picture of that system before you remove it on the weekend. I still haven't seen what the KSU looks like.

Very close, Twisted, but incorrect. The common control lead (A1) is the orange/white, not white/orange.

Also, Western Electric (AT&T) stopped using common grounds for the lamps on 10/20/30 button sets pretty early-on, but ITT (Cortelco) and Comdial (Stromberg-Carlson) continued to provide a copper strip that tied all of the lamp grounds together. I didn't work with Northern Telecom sets much (Logic 10 and 20), but the wiring was almost identical to Western Electric.

The 10 button phones pretty much used 2 1/2 pairs per line, one for the CO line T/R, one for the lamp (LG/L), and the half-pair for the "A" lead. Only one common lead ("A1") was required regardless of the number of buttons. With this arrangement, there were not many spare pairs to throw around for extra stuff, like transfer keys.

That's when we started stealing those lamp ground leads. It was amazing how much progress you could make by just having one extra single wire available to work with.

Man, you just lost the grand prize, a 2006 Hummer H2 and perfect 21-30 year-old women to fill every seat. You need to be more careful with your answers next time!

I am still impressed that you knew that much about a tried and true, yet dead technology.

If you want to see a 1A2 KSU, I will send you one if you pay for the postage.

Aaahhh, man, I could have used a hummer!!

Do I have the rest of the wiring right or are you going to make me wait for Ken to answer that?

I should take you up on that offer, wire up my 2 old sets to the 1A2 and learn a little something...........like why I'm lucky I got into the business at the point that I did maybe!!

Hummer, hummer? I thought were taking about old phone systems not well ah, the ah ... oh never mind, get your minds out of the gutter and tell them how much money you made on replacing burned out fuses and burned out bulbs in the keys, the clear plastic line buttons, not the piano keys.

How many of you could make an a lead on a s/l phone without looking at the wiring diagram in the box, are you that good?

True story, little old lady came in with her favorite old AT&T desk phone that didn't ring any longer and just had to replace one slate wire to go Harrring, harrrring, harrrrring.

I think you should wire a 20 station Stromberg Carlson while you are drinking and posting on Saturday.

And do you remember that GTE used similar equipment that they classified 10A2, not 1A2.

Remember what confidencers are and who was the ONE company that actually made one that worked.

WOW!!!! Now I really feel old! I started with uncle sam doing 1A1 key systems. There were just a couple of things that you didn't loose. Your butt, telephone test set and your wire wrap tool. All in that order. I thought that Christmas came when they gave us the "zip" gun. Whew...old age. I wish I had .10 for every lamp I changed. I sure changed a lot of them on the 5, 10 and 20 button sets. RBF, if you want to really blow them away, explain the diode matrix ringing to them! LOL

What is a confidencer?

I was doing some reading on the diode matrix on some old posts here. Sounds like it was a lot of fun when you were dealing with 60 phones and 10 lines all ringing differently. Was this matrix done right on a 66 block?

EV, You are correct about those ring tranfer switches causing diode matrix ringing nightmares . If not properly installed key phones that did not share the same key lines but had a transfer switch connected to the bell in thier phone would cause the bell to ring but no key lines would light up and flash . One of the early causes of phantom ringing on key sets . Also why did some companys take the hundred pair cable on the 1a2 call commander phones and break them out into 5 amphenol connectors ? There must of been a reason !

OBTW:

Early large key sets, such as call directors, had these "five-finger" 100 pair cables that were used to actually plug directly into the key strips in the phone. The line cord was just a male to female five-finger cable. I guess this was an effort to reduce manufacturing expense and complexity.

Twisted:

I almost forgot, yes a diode matrix could be done using a standard 66 block, but Western Electric made a special block for this purpose. It consisted of five vertical rows of clips and five horizontal rows. I diode was then punched down at the desired cross points to activate the ringing for that line. These blocks could be daisy-chained to accommodate any number of lines and stations.

twisted... we did them on bix

100 pair cable for the call directors & 30 ,60 ,90 & 120 line bucket ,s wired up like 5 6 button phones & had plenty of spares, lota fun looking for a bad diode out of 100 line console not ringing or dinging

Telemarv:
That supprises me that you did them on BIX. The reason I say that; because I have been in lots of phone rooms that had the remnants of 1A1 & 1A2 and there's always walls of 66 blocks. I didn't realize we were using BIX here in the great white north that long.

Ed:
They made a category for 1A2 with you as the moderator :rofl: Sucks to be you!!

Next trivia question; where did the A1 control lead term come from? Or for that matter, 1A1, 1A2? I assume that LG came from "lamp ground?"

Simon:

The A lead is just a ground that is switched by the hookswitch and hold button inside the set. I guess they just needed two terms for either end of what is effectively a loop.

1A1 and 1A2, or GTE's 10A2 were just nomenclature for the family of hardware, just like 5ESS. 1A1 was the first generation of modular key systems made by Western Electric and when a major change came about (plug-in cards instead of hard wired KTU's(relay units)), it became 1A2. 5ESS is simply the fifth generation of AT&T's electronic switching system, the first one obviously being 1. By the way, there are still plenty of #1ESS switches in use (actually 1A's) and 4's in North America.

Oh, and yes, LG is Lamp Ground. Ding ding ding, tell him what he won, Johnny!

We had modified Logic 20s with non locking keys and a 20 button addon and the set was called a logic 40 that would work on a 50 pair cable almost 40 lines and you could add to each 40 button set another 20 button module. There was a limit how many you could put on. There was only one talk pair for all the lines and 1 A lead and 1 lamp lead for each line and the grounds were commoned up. It was sort of a concentrator It saved a lot on cabling.

Okay, kids, get to your seats and open your books to page 7. This class is entitled "Telecomm 101".

Three pair per line

Pair 1 --- Tip and Ring --- Talk Path.
Pair 2 --- A and A1 --- Battery and ground to operate relays (Hold, etc.)
Pair 3 --- Lamp and Lamp Ground ---- Lights!

Just Bill can tell you about the Central Office Toll / inter-office circuits ---- relays IDed by letters. The "A" refers to the action it controls by the "A" relay. "E&M" circuits (EAR & MOUTH) sent and received battery and ground to control the particular operation. Just like ground start trunking.

Next week we will cover "Wink" and how it starts (play on words, wouldn't you say?) :read:

Have a nice recess, class dismissed.


KLD

Thanks a lot guys for the lessons on the old 1A stuff. I never did much work with them but did replace many of them with EKT's I have an older friend that still has tons of this stuff in his now closed shop. He repaired AT&T systems for decades and taught me all I know about the 1A2 and Merlins

Yeah, it is kind of cool learning how this old stuff worked. It looked scarey, but in all fact, it was kind of simple technology. I just wish I could impress someone now with my new found knowledge! Maybe.....it's like Ed said, this stuff is making a bit of a come back.

Ok, I learned on a 10 button set they still used a 25pair line cord. What did they do with the 20 and up sets? Two 25pair cords?

They used a common ground on the A lead, so you only needed one wire instead of two.

Twisted:

20 button sets had a 50 pair line cord and 30 button sets had 75 pair. Call Directors had 100 pair, but it was five 20 pair binders instead of the traditional four 25 pair binders. Same 25 pair connectors, just no violet pairs.

Hey, Ed, are we having fun yet?

KLD

Anyone remeber the old rotary dial auotodialers you could connect to a 1a2 key telephone . They looked like a old rolodex file and the numbers were stored on magnectic tape ?

I have seen them only in books and have never worked with them. I bought something similar to that that I got at a yard sale back in the 1970's. It used a continous mylar loop with little dots you filled in with pencil for each phone number. You slid the pointer on the cover to the appropriate entry and pushed the start button. The sheet moved across a set of contacts which picked up the number of dots you filled in for each number creating rotary dial pulses. It actually worked, but it was a piece of junk! I guess it was technology from the 1960's or so.

How about tape readers for the teletypes? Ok I know it has nothing to do with 1A2, just checking out Ed's age factor.

The 1a2 key phones I disliked working on the most were the Stromberg/Carlson models . The line buttons would break/stick , the faceplate would never stay on correctly , the 25 pair cable would pull loose from the phonebase housing and if you dropped one the bell would jam first time every time . Anyone else have one model they thought was junk ?

I do agree with you on that. S/C (Comdial) sets were the most problematic of all brands. The thing I disliked most was their new electronic dial that wired completely differently than any other brands. And those damned push-on spade tip connectors on everything!

Now if you want a truly ugly 1A2 phone series, then Automatic Electric (GTE) phones win hands-down.

Bill, yes, I have used a teletype with the paper tape reader. It was during my junior year in high school in 1977 for a computer class. The mainframe was at the school on the other side of town. They had NJ Bell run a 1,200 BAUD point-to-point data circuit to our "computer room". We wrote our programs using BASIC language and stored them on tape. The bigger your roll of tape, the more elaborate your program was. Wow, how times have changed. There, I said it. Now you can guess at my age!

:dance:

Re-perferator and all ---- yep, and with radio relay it could "burst" allowing for code privacy.

How abnout the 1A2 auto-dialer that looked like a square credit card machine and used credit card like punch cards --- one for each number. Insert it , go off hook, and punch the start button. The card would rise up the slot and dial the number. That's how I used to order my supplies from SWBT and WE.

KLD

And they thought I was old! Mr. KLD, you have just admitted that you are older than I am. The defense rests. Your witness, Mike?

confidencer was a handset microphone that cut out background noise. screw off regular transmitter, screw on confidencer. kind of a small rim around it keeping out background noise.

the matrix could be "locally" made on the 66 block or i think it was a western electric product pre-made.

Okay, Twisted Pair, I sent you a set of pictures via e-mail. I'm too dumb to figure out how to get them posted here.

An ITT 512 has card slots for up to 13 COs. Their shoebox (601) was good for 4 from the factory but I have had it support more with some "creative" wiring. Also dial intercoms. The WECO 551 series wasn't as flexible.

Any questions, let me know.

KLD

OOOOPs, EV --- Ed --- you know, that old man. I probably have to plead guilty to that one --- just survived longer than most.

Okay, roll me out to the sunny side of the porch so I can say "Good nnnnn---------- "

Hey, Ken. The ITT601 was ready to go for five lines AND they had a plug-in 10-station intercom card that plugged in the bottom slot. All that was needed was the appropriate number of line cards. Of course, if Touch Tone intercom was desired, a piggyback card was required. The 601 had all of the regular power connections available if you wanted to use an external intercom, like a Melco or Tone Commander unit.

From KLD:
Thanks KLD for the pics!

I'm going to attempt to post the 2nd one here (the one without your customers mug shot)

Why do they call the 1A2 a "shoebox" KSU?
It's pretty large and I take it that the cover is removed for the pic. With the cover on it would be even larger.

This one is not a "shoebox" --- The WECO 551s and ITT 601s were much smaller --- about the size of a shoe box thereby the name.

This one is the next size up --- I'll measure it and give you the exact size. And, YES, the cover was big enough to give your golden retriever a bath in.

KLD

And, Ed, once again you prove that I AM the older, Oldhiemers and all --- roll me back out into the sun, please :bow:

KLD

:shhh: Ken I remember ordering supplies with the card dialers..don't tell Ed :shhh:

At least when we installed 1a2 for customers we did not have to answer all those inane questions about Caller ID .

So in that picture; what is located right beside the power supply on the left side?

It appears to be an 89b bracket and a transformer . If I had to guess ! Which this is only a guess !

I'm back and I heard you guys talking about me. The shadow knows.

On ITT 512 KSU's, there was a small fuse panel mounted to the left of the power supply on the mounting rails. It utilized flat fuses. I don't believe that any other manufacturer did this, except possibly Stromberg-Carlson, so I am pretty sure it's an ITT.

Now as for that thing to the left of the KSU itself, your guess is as good as mine!

It looked like a fuse panel, that supprised me though, the power supply also has flat fuses on it (I have one). ITT must have liked the extra protection?

Nice Avatar Simon! That's an oldie but goodie!

Yes, it is a supplemental fuse panel, but not like what you would think, as in secondary surge protection. It just was used to split out the high-amperage outputs of the power supply into groups of line card slots.

The 512 KSU that ITT made was a variation of a Western Electric 584 panel on a rack with a cover. It wasn't truly a 584 panel though, because 584's had lots of fuses to localize power distribution to the individual cards or groups of cards. While the 512 was still a 13-line KSU, it lacked this individual localized fusing of high-current outputs, like lamp power.

Even with small phone stuff, those 1A2 power supplies threw out a lot of amperage, sometimes 10 amps. A short under a single 10 amp fuse would have certainly caused a risk of fire. I mean, 18 gauge wire is rated to carry that amperage, but when you get down to 26 gauge line cord conductors, it could get ugly.

Those fuses were just there to break the 10 amp output into more managable 2.5 amp circuits. I am sure it was a UL/CSA requirement.

Thanks Ed, I knew you would appreciate it! I have had a renewed interest in the old stuff and I pulled out my old sets including an old 3 slot payphone and started restoring. I did a search for some old logos to install in the dial and found that.

I use to work for a company that did alot of the powered paging speaker systems. We use to find those old power supplies and use them for the speakers. You're right, they are power houses. Before we started fusing individual lines, I had seen twisted pair melted into a single conductor and that 10 amp fuse never blew.

Sorry, guys, been off the board a couple of nights. Yes, Ed called it. If you look "under" the power supply you'll see where the amp cables plugged in to go to the 66 blocks for fan out.
This one had an exterior mounted Tone Commander 1900 series ICM and all ten button sets, including three wall sets.

And, OBTW is so right ---- NO CID>

KLD

A confidencer is a device which screwed onto a g-series handset which supposedly helped prevent your voice from traveling through your office area.

I have loads of 1a2 equipment, touchamatic dialers, 4a speakerphones, if anyone is interested.
mm

Ahh the good ol days, before IP, patches, patches, patches. I think the Confidencer was the secure handset transmitter used to prevent the Russians from listening in on the old 1a2 key stuff. Hey I use to work on the 1a1 w/ the old 207c intercom wipers and cleaning carbon relays all day. 1a2 was high tech, still love that a-lead and man cave stuff. Still have the 10v lamps, #1 troubleshooting tool back then, besides a screw driver.

that's so true. Put a lamp in the lamp lead at the 66 block, short the a-a1 to see if you were good out of the key system, also good when you weren't getting the intercom ring on buzzers, just put a lamp on the buzzer lead, same with testing button and buzzer.. The good ol' days??