Hi guys,
I'm pretty new to 1A2. I salvaged an old KSU from work that I discovered in the sprinkler closet during our re-cabling project and thought it would be fun to make it work again. It still had power when I took it off the wall, but there have been at least two other phone systems since it was replaced (at least 15 years ago).
I took the KSU home and hooked it up to a few 564 and 2564 stations with help from bits of documents and drawings online. I'm using an Asterisk box to provide dialtone. I've also got a Melco KC-19 for intercom. At some point I'd like to add a 10 button station to the mix.
I found some documentation online and while it isn't for my particular KSU, it's pretty close. However, it was a pretty low resolution scan and the page with the station block layouts is pretty hard to read. So, to make things easier for me, I drew up what I believe to be a correct drawing of 6, 10 and 20 button station block layouts and I was hoping someone here would be willing to proof it. Drawing:
Typical Station Block Layouts Many thanks,
Tim
PS. I may send more of these your way, since all of the drawings I have now are pretty bad.
I'm not sure, but why does it skip pairs?
Tim -
Going from memory it looks right. I'll try to dig up the docs tomorrow and check. I do remember that Northern Electric/Telecom Logic 10 & 20 sets were different then WE/ITT/AE/Stromberg sets after the first 6 lines. (So watch out for those)
Jeff -
When you say "skip pairs" are you referring to the "A" leads jumping around and/or the Y/O, Y/Sl pairs?
On a six button set the first five lines went in order. Yellow/orange was the Intercom Buzzer, Yellow/ Green was the Hold Lamp and Yellow/ Slate was the Ringer. When they went to 10 button sets on 25 pair they tried to keep those signalling pairs standard.
Sam
I'm not sure, but why does it skip pairs?
Not sure either, but that's what the original looked like; there was definitely no text for the unlabeled pairs. The others were labeled, but blurry, so I made my own drawing. The empty pair for the 10 and 20 button blocks makes sense though, since there is only 1 A1 lead and 6A appears after 5A. However, the 3-1/2 blank pairs between 5L and SG on the 6 button block seems strange to me.
It's right. The pairs aren't skipped, they make logical sense so the TRa/Ax/Lg/L stays in order.
On a 10 button set, you fold a2/a9 a3/a8 a4/a7 and a5/a6 into the pairs and you always have T&R every 3rd pair. The only extremely weird punching is the L/L9 moves into the 23rd pair.
If you got extremely lazy and ran out of 3 pair jumper wire, you could install a 1a2 system with 2 pair jumpers after the 1st line. Of course, it was required and made for a neater looking frame if you actually did that, otherwise you ended up with a spare wire from every jumper hanging in the frame.
Carl
of 3 pair
Ok for example on the drawing
2T
2R
2A
blank
LG
L
Shouldn't the blank space be A1?
A1 leads were common, that's how you made the 10 and 20 button sets work. On the 6 button sets they were punched down as A, A1, but in the actual set they were spares.
It seems like the 10 and 20 button sets did away with the SG lead. What was its intended purpose?
Some of the 6 button sets I have used SG (BN-YL) and the OR-YL lead for the buzzer and the others used the OR-YL/YL-OR pair.
SG was Signal Ground. The ground part of the buzzer circuit (generally associated with an Intercom) Yellow/Orange, Orange/Yellow was the standard for buzzers, but I think Y/Br, Br/Y may have been a secondary buzzer.I'm pretty sure it was the buzzer pair for NT Logic sets.
The 6 button set had so many spares that they almost made up stuff to put on them.
They also had 12 button, 18 button and 30 button sets (Call Directors) that took 50 pr, 75pr and 125 pair feeds - though the 30 button call directors came out with 5 amphenols of 20 pair each - they left off the violets because there were so many spares.
When the 10 & 20 button sets came out, it was a big improvement and then the 30 button (2860 maybe?) came out and ran on "only" 75 pair!
Sam
Interesting stuff guys! See, I learn something every day here!
Your drawings are correct.
You might want to see if you can pick up on Ebay a copy of "Key Systems Service Manual", Vol I (tel sets) and Vol II (KSU's).
I installed and repaired approximately 3.7 zillion of these over the 30 years of my career. If you have a question, email me. One place I worked had 12,000 key sets, and 300 equipment closets. Every cable was a home-run, and we used no bridging clips.
Mount 66M-50 blocks and terminate the 25-pair running cables for each station, two to a block. Then you need to bring out all the features (that's what we call the TRAL&LG leads) on a 66B-25 block. It needs to be mounted on standoffs if you can't find the rare mounting brackets. I have used 3/4-inch long pieces of 1/2 inch thinwall conduit, or plastic tubing, with the mounting screws running through them, so that their front faces are even with the 66M-50 blocks of the station cables.
Mount some mushrooms for the 3-pair cross-connection wires to run around, and cross-connect the features to the appropriate buttons. The first X-conn to any station's first PU key uses all 6 wires. Subsequent X-conns use 5 wires. All 6 leads are punched down at the feature block, and at the station block, the O/W lead is carefully wrapped ("whipped")around the other 5 leads to keep them neat and tidy.
If this were a real installation, you would need to create enough feature blocks, using multiple wires, so that you do not need to use bridging clips at the 66M-50 blocks. That makes trouble-shooting easier. For your application, bridging clips can be used, but remember that any two phones that do not share all features still need individual X-conns.
For the dial ICM X-conns, the convention is T&R (Bl/W pair) Lg&L (Gr/W pair) and the O/W pair is used for the buzzer pair.
Aurthur, I contend that there is nothing prettier than the backboard of a well done 1A2 system with 2-3 13 cell racks, 50-60 10/20 button phones, lamp extenders, 2-3 intercoms spread across the phones with some phones having 2 or more I/C paths, and, of course, ring matrixs' all over the place. The only problem is you'd need a panoramic camera to take a picture of the 15 feet of backboard! And what fun watching the never-seen-1 youngsters.
John C. (Not Garand)
John -
While my home setup isn't that spectacular, I do have on order red and blue backboards for the key system blocks and the station blocks. Also, some white backboards pre-populated with spools for routing the wiring. A diode matrix would make a nice addition, if anyone has one laying around
-Tim
Genuine matrix blocks are hard to find unless you can scavenge them from an old equipment closet in an office building. They take up a lot of space, so at AT&T we used to make our own, to save space on our backboards. Our home-made model fit right in with the rest of the 66-type blocks, and were easier to label and to maintain.
A diode matrix block can be made very simply and neatly from a 66B-25 or -50 block. Release the tabs on the back, and slide the back of the block off, and dump out and discard all the metal pins. Then take a 66M-50 and do the same, but carefully collect the pins from the M block.
Then put the two-position pins from the M block back into the B block, so that there is a space down the middle with no pins (what would be rows "C" and "D".) Take a bunch of diodes and terminate them in the empty space, one lead on row "B" and one lead on Row "E". The pins at row "F" can be looped...as many as needed...and sent to a station's CMB lead. The pins on row "A" come from the line card CMB leads. Don't forget to face all the diodes the same direction, (cathodes facing to the right) and to wire the ringers for "no capacitor".
The wiring convention we used for those 12,000 sets in one hospital was a single green lead from the 400D card to the matrix, and a single red lead from the matrix to the set's Slate/Yellow lead. The ground return (set's Yellow/Slate) was a single black wire to a 66 block that was nothing but ground.
Do you have any pictures of a setup like this?
Jeff:
You mean the matrix block, alone, or an entire installation?
Sorry, I have pictures of neither. I have no talent for photography, and my time machine will be going into the shop last Wednesday, if I can remember when I parked it.
I can make a matrix block as described above, and take a photo, if that's what you'd like to see. It might take me a few days.
I thought I remembered a picture of the matrix block here at one time...
yes, that was it. thanks!