atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems Project 1A2: Phase I complete.

Well, what I did was to run a 25 pair from the KSU over to the upper left 25 block. The block below that is for intercom connections.

From there, I run cross connects from both the the upper and lower leftmost blocks (I forget what Ed called them, basically the only difference I see is they are gray and no clips are required) over to the others.

There are (6) 6 pair cross connects going from each "row" back over to the gray blocks. 1 6 pair for each line, and 1 6 pair for intercom.

Dunno if that's the proper way to do cross conencts, but it seemed like running independent lines from each row of blocks back to the gray blocks would help with troubleshooting, rather than daisy chaining all the 66 blocks together.

Also, I fixed the intecom problem. Ed shipped me a new intercom and power supply card, but the IC card didn't fix the problem. It would work, but only intermittently.

So what I did was to put the Melco back up, and power it from a Valcom filtered talk battery I had.

For the 10v and 18v feeds to the Melco, I use the KSU power supply. Probably not something that's recommended, as I can see why having 2 power supplies could cause smoke problems. I was very careful to keep them isolated from each other. So now I've got no hum on the intercom talk path.

Now if I could just get MOH working...

Dunno if that answers your question. Basically all the cross conencts run behind the blocks and over the shrooms. Was there another way I was supposed to do it?

Thanks Sam!

The usual way of doing cross connects is to run them on the outside of the block and on top of the mushrooms.
Here are a few examples of Ed's work
https://i98.photobucket.com/albums/l268/ev607797/Homesystem.jpg

https://s98.photobucket.com/albums/l268/ev607797/?action=view&current=e7e82e1d.jpg

https://i98.photobucket.com/albums/l268/ev607797/evpics013.jpg

Oh!

Well, I can see how that would improve your ability to find things. There's enough slack to pull them from behind and route them in front.... perhaps something to do tonight.

Thanks Jeff -

Matt

You got it!
I should take pics of how I have my cross connects at home- I will do that this weekend.

Yes, the whole concept of terminating ("heading up") cables on blocks, and then running cross-connections to interconnect the circuits is so that the ends of the cables are never touched again. Before x-conns were "invented" the ends of the cables were jammed into the KSU cabinet, and just the wires that were needed were extracted and terminated, and subsequent visits would result in shorter and shorter leads, and a real bird's nest of wires.

The x-conns are expendable, moveable, and traceable, as shown in the third photo from Jeff. Every job should look so good, Jeff.

The reason the two left-most (assumed 25-pair) blocks are grey is so that they are distinguishable from the 50-pair white ones.

The grey ones give you three sets of output leads, capable of feeding three telephones, or 6 telephones using bridging clips. (Using bridging clips assumes that 2 telephones, fed by 2 cables terminated on adjacent sides of a single 50-pair block will be receiving the exact same features.) That is a reasonable assumption in your case, but in the real world, the output cables from the KSU would be terminated on a minimum of a 66B25 block, which is longer and wider, and has one "input" clip and five "output" clips per row, allowing up to ten stations (with the bridging clip method) to be fed. In a very large installation, the KSU feed might be multipled on several more 66B25 blocks, so that every x-conn would serve an individual phone, with no bridging clips.

We had a rule that said no bridging clips, everything a home run, and everything a cross-connection, regardless of expedience. That method, applied as a standard in a big place, made every installation harder, but made repair clearing times (the index by which customer satisfaction was rated) very low.

(Of course, a harder installation equated to bigger paychecks, and that was OUR index of satisfaction.)

We had an 8,000 line, 600 trunk PBX with more than 12,000 key sets to maintain, and that method was the only thing that kept the whole place from being chaotic.

30 years from now, we'll have taught you everything there is to know about 1A2.

I wish that job was mine...It was Ed's work

Arthur -

Thanks - that explains a lot. I always wondered how it would be handled for companies with 20 or more lines. Now I know.....

But it's gonna take more like 60 years, or even 120 to learn it all, since I only work on it about 20 hours a week (and half of that time is spent tearing it apart and redoing it. Let's just say it's a good thing I have short runs and long cables.

Jeff -

Thanks - look forward to seeing them!

- Matt

Here's a question, I tried to zoom in on Ed's pics but they pixilate too much to see.

As I'm running the cross connects, do I use cable ties to keep all the 3 pairs together as they branch off into the blocks, or is there some other way this is done?

Thanks
Matt

Sometimes if we had a lot of x-connects, we would take little pieces of scrap wire and LOOSELY tie the group of x-con's together into one bundle. This would keep it neat, but would allow the individual wires to be pulled and traced. Tight ties or even worse, tiewraps were a big no-no.

BTW - the x-connects themselves should not be tight (No banjo strings). We always left a "drip loop" at each end so you could see them move and ID them when you pulled them from block to block.

Ideally, you should be running 3 pair x-con for the lines and single pair for the bells. buzzers, etc. Sometimes people would use the whole 3 pair for the Icm - W/Bl for T/R, W/Gn for LG/L and the W/O pair for B/R, though purists would say you should turn back the W/O pair and twist it around the rest of the X-con (so it was easily identifiable as an ICM cross).

I did a large hospital once and used W/Bl for Patient phones, W/O for Admin phones, 3 pair for key equipment (of course) and then I customized the trunks - V/W for OGT (Dial 9), Y/Bl for DIDs, BN/W for Paging, etc. I posted a sign explaining the system and left spools of each kind of X-Con hanging on a piece of pipe.

When I went back to add a cabinet a year later I found that the MAC guys had let the whole system go to hell. Boy, was I ticked.

Sam