atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring I need some help on the basics

Hal do you mean 26 pair inside wiring cable? there was such a thing, the last pair was a red/white; made up so western could guarntee 25 good pair in a cable, also called interstael in outside cable -silk and cotton/ paper/pulp.

No, never saw that cable. Would it be used with connectors? If so that might be the answer.

-Hal

Hal -

We got 26 pair cable occasionally. It was a "standard" IW cable with a Red/White pair. I was told the extra pair was used as a "talk" pair by splicers, but I never believed it. OSP yes, IW? No.

We used to get it in the early '70s from a cable supplier upstate. I never really got a straight answer on it. It was quite a shocker the first time I punched it down. I remember asking if we could order it and have it ID'd (it used to come in mixed with a batch of regular 25 pair). I remember thinking it would be good to have it for the attendant/operator position (where they always wanted something extra, like a door release button) but the supplier couldn't or wouldn't guarantee it.

Sam

The 26th pair was supposedly a "talk pair" back when pulp cable was used where all of the binder's pair colors were the same.

It also existed in inside wiring cable well into the 1960's until cable pairs became "band-marked" and solid colors in pairs went away. After that, the 26th pair went away on indoor cable for the most part.

It carried over into PIC cable for a while, but was usually used as a "frog" pair (temporary replacement for a bad pair). Aside from T-Screen cable, I haven't seen any 26th pairs around in a while. I think that I still have some icky-pick 52 pair T-Screen cable, where there are two separately-shielded 25 pair compartments, with a white/red spare for compartment #1 and a white/black spare for compartment #2.

We've kind'a hijacked Sparkies thread. What say we try to get it back on track. Don't think he was looking to get quite this deep just yet.

Extra pairs are pretty common in OSP cables, usually when they find a defect they cram a few extra "just in case" pairs into them.

Once again... WOW. :bow: Sorry it took me so long to post again. I was traveling and my laptop crashed. Not only could I not communicate but I couldn't get any work done either.

While I understood a fair percentage :confused: of what most of you were talking about, it is light years above my skill level for voice. I wouldn't even try to teach anything at that level. I would love, however, to be in your neighborhood when you were doing some of that stuff. I'd work with ya for free just to get the experience! The systems that I typically work on, and have been asked to teach about, involve typically a maximum of a couple hundred drops fed through the usual MC - IC - HC TIA/EIA 568B stuff. Usually the voice involves a 25 pair cable from the CO. My problem is that every voice installation of any significance in which I have been involved was specified with patch panels, usually on a rack. Also, they specified Cat 5E or Cat 6 cabling with 8P8C jacks of equivalent rating for the voice (I'll bet you can't guess why they specified it that way ). I'm taking over this class from somebody else that taught it for one year and quit. Looking over the material he used last year, I don't see anything involving cross-connecting voice or bringing in the CO. It all starts at the MC as if the incoming voice lines don't even exist. I could just teach the same thing that he taught but I want to address this specific scope of work because nobody taught this to me at any of the BICSI classes that I took and it remains a weak area of my understanding. This is probably why sparky's and CG's screw everything up so much, and I see this as a chance to make a difference. OK, enough rambling. I think you all have a pretty good idea of what I'm trying to accomplish by now so... Back to the questions:

IF you don't know what type of phone system is going to be installed on a small system with 25 prs coming into the building, how would you handle the punch down? Lets say you have 50 drops with each one including (1) voice and (1) data outlet and the provider has mounted a 66 block as the demarc. In my office, I mounted an empty patch panel on the rack for my telphone guy to use. He mounted the telephone system (NEC Aspire IP1NA KSU) on the board and dropped a 25 pair cable out of it. He split the cable, running some pairs to the demarc to pick up the CO lines and the others to the patch panel that I provided in the rack. He labeled the Patch Panel with the various extension numbers from the phone system and also provided (1) port each for the incoming lines (I guess he did this for testing purposes, I don't use these ports). I patched the extensions to the other patch panel mounted on the same rack on which I punched down the station voice cables. Does this sound like a typical installation? With the exception of the demarc, everything is on a wall mounted rack because at the time I didn't know any better. If you were faced with the same scenario and you did not know what type of phone system, if any, was going to be installed, how would you do it?

Sparky,

Just think of the incoming lines as if they are dedicated electrical circuits.

Think of the KSU as a Master Panel.

Think of station cabling the same as dedicated circuits from the Master Panel.

Rule of thumb for both voice and data....no more than three x-connects or "hubs".

Now then, think of a KSU as a CPU on your home computer. The feeders are the same as the DSL or cable input. The KSU does the "mixing" so that the users get inter-connection and outside connections. Think of the station ports no differently than ports for a printer.

Know anything about networking?

Server in the middle of the "hub" and a bunch of computers. KSU in the middle of the "hub" and a bunch of phones.

I also taught electricians and taught in many areas of the US of A. I do speak "Sparky" as well as "Telephonese".

Ken.

The preferred method of terminating your drops should not be a patch panel. I prefer either 66 blocks with ALL pairs terminated on their own pins. Or the 110 version with the same result. The prior being most preferred.

The feeder should be terminated the same. Never mind if you know what system is going in all telecom pro's will match what they see on a back board. Providing there is room anyway.



Note the demarc on the right.

My problem is that every voice installation of any significance in which I have been involved was specified with patch panels...

Never use patch panels. That was obviously specified by a geek.

usually on a rack.

Lose the rack too!

Also, they specified Cat 5E or Cat 6 cabling with 8P8C jacks of equivalent rating for the voice

Yup, it was a geek alright. Real men don't use CAT5 or 6 for voice.

I think you have a tough row to hoe if you want to teach this stuff. It looks like you are just as confused as your students. You are confused because of the crap the geeks want and the BICSI stuff. Forget all that and just study the picture above. THAT'S how a telephone system is done. No patch panels, no CAT5, no "RJ45" jacks.

The white drops from the jacks are on the left and get individually punched down in order (Left to right, top to bottom jack 1 will be on block 1, clips 1-8) on the split 50 pair 66 blocks, looks like 1 through 16.

The station port 25 pair cables from the system get punched down in order (again left to right, top to bottom) on blocks 17-22.

A single pair white/blue crossconnect wire then runs (jumpers) from the station blocks to the premises wiring blocks to connect the system extension to the jack wiring. That's what you see running down around the spools then back up.

The CO DEMARC is on the far right. In this case the lines may be brought in on PRI because I don't see any cross connect wiring. But for normal CO trunks the method is the same as the extension/jack premises wiring. There will be a block on the right with the CO lines on it as part of the DEMARC. There will also be a block to the right of the last system extension block for the system CO lines. Each CO line gets connected (again with cross connect wire) from the DEMARC block to the system CO lines block.

Dedicated CO lines such as for a fax, modem or credit card machine that are not associated with the system get cross connected directly from the CO DEMARC block right over to the clips on the block for the jack where they will be connected.

That's all you need to know.

-Hal