Nordx/CDT Troubleshooting-HELP NEEDED!

I work for a small private college located in Toronto, Canada. I teach Networking there and so got delegated to put in the network at our new campus. The location of the new campus was previously occupied by a bank, who used the Nordx/CDT IBDN system for their LAN & telecom. Wanting to have a "professional" network, as well as leveraging the existing infrastructure, I decided to do all 210+ LAN drops using the Nordx/CDT. In hindsight, I realize that I probably would have been better off to just use patch panels but no longer have that luxury. Everything seemed to go fine after hours upon hours of punching down, but now that I am doing end-to-end testing, I have approximately 25-30% of my LAN drops not working, which is a big problem. Using a LAN Cable tester, I find that with each of the problem ports there is one to two pins not showing up--even after punching them back down a second (and third time). I have been searching the web and can't find much, if any, documentation on how to properly troubleshoot this system so that I can identify, isolate, and resolve the issues. Considering that there are five points of contact from end-to-end, I am not able to readily determine which contact is giving me the problem. I have a place here in Toronto where I could rent an expensive test tool but am not sure which tool I would need (ie: Fluke Omniscanner 2, Agilent WireScope, etc). The college have classes scheduled and need the rooms/network to be fully functional, so I am running out of time. Any recommendations for how to approach the troubleshooting, what tools would best help in this situation, and/or pointing me to any documentation would be greatly appreciated. Thanks in advance!

Best regards,

Greg

Gregory Seaborn

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Reply to
gseaborn
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I'm not quite sure what you have, as 'Nordx/CDT' is just a brand name. Like Panduit or Hubbell. It looks like their 'IBDN' system is mostly

110-blocks, but they do have IBDN patch panels, so more info is needed for what you are using that isn't a patch panel. (do you mean that the cross-connects are just punched down wire instead of patched in at every location? Thats fairly normal).

In general, for a large structured wire system that you are unfamilure with, the biggest problem is going to be punching the jacks. Its probably easiest to test the 110-block fields first, you can buy test plugs that fit over 110-block pins and come out to an RJ-45 for you. (ie. I have a siemon TAP-110-A4 on my desk I'm looking at).

Buy a few of those, setup your tester with your helper at the next panel, and just go through the block field quickly.

If you don't have a helper, recruit one, it'll make these sort of tests go much quicker.

Then you can move onto testing from the 110-block closest to the jack and out. Run around, from jack to jack with your helper at the block field with the 110 test clip, and it should get you tested one segment at a time fairly quickly.

But as I started with, the jacks are usually the ones that are not good. As these jacks are getting higher and higher density to get the cross-talk down, I've found it good to have a "punching puck" which cradles the jack and holds it firm while you punch the wires down. They are kind of hard to find (ie. not buckets filled at the wire distributer will-call desk, they have to order them in special, etc), so I don't think many use them. I have seen many jacks out in the field with one wire clip broken, or opened up from the punch down tool slipping. Don't know how they certified it, probably lied and moved on. This is probably problem #1 on doing the jacks, the wire clip opened up just a little, and not good connectivity any longer.

As for tools to rent, anything with the TDR graphing function would be good if you know the aproximate lengths of the wire runs. That would at least show you where the signal isn't getting through. I don't have alot of experience with the expensive tools in this range though.

Reply to
Doug McIntyre

Hi Greg,

I guess the most general approach to troubleshooting you can take is to remove any parts of the system you can until you are left with the simplest channel, test it and if it test out fine, start adding pieces until you add one that makes it fail. That way you would what's failing. In the case of the cabling channel the simplest you can get is the cable and the two corresponding connectors on the ends - modular jack at workstation and patch panel/cross connect in the closet.

As far as your actual setup, looks like you are using IBDN but as Doug pointed out they do have different types of punch-down connections and knowing which ones you are using might help.

When you say one/two pins not showing, are they consistently same number pins? Also, individual pins or pairs? I have seen cases with pairs consistently being lost because some of the installers were not familiar with pin payout of the jacks and mixed connector in pairs. Could this be the case here? In any case, if you are able to identify any pattern of failures it would help you tremendously. If they are completely random, then you are obviously looking at many different issues each needing its own fix.

The equipment you've mentioned is probably overkill in most cases except some (rare) instances of grossly improper cable handling that led to ripped/broken conductors in the cable. In all other cases the problem is in a connector and cable scanners, as good as they are in testing cables, cannot tell you much about an individual connector. On the other hand, if you for some reason cannot strip your cable channel down to just the cable and two end connectors, then by using the TDR (TDX etc.) function you can see that if a connector is missing where it should have been present, you know that something is wrong with that connector.

Anyways, remove all non-essential parts so you are testing the bare-bones cabling link and look for patterns in the faults. Post more info here, too. These problems are hard to troubleshoot remotely but sometimes a familiar symptom may reveal itself to someone reading this.

Good luck!

------------------------------------- Best Regards, Dmitri Abaimov, RCDD

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Reply to
Dmitri(cabling-Design.com

gseaborn wrote in part:

Doug & Dmitri have given you great answers, I would just add to be _very_ careful of your punchdown tools. Make sure you use the right blade -- the common 110 does not work on all IDC, and IIRC Nordx uses different tools (double IDC?). You can mash the teeth, especially with oh-so-convenient&satisfying impact cutoff. A puck or block of wood is essential for impact.

Missing 1 & 2 pins at random sounds like this intermittant. Had it been missing regular pairs, I would suspect some crossconnect wiring for doubling up.

If this isn't it and you want to test further, get a tester with time-of-flight. It will tell you where the open is.

-- Robert

Reply to
Robert Redelmeier

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