Nordx/CDT Troubleshooting-HELP NEEDED!

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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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Re: Nordx/CDT Troubleshooting-HELP NEEDED!


gseaborn_at_gmail_dot_com@foo.com (gseaborn) writes:
Quoted text here. Click to load it

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.


Re: Nordx/CDT Troubleshooting-HELP NEEDED!


Dmitri(cabling-Design.com) had written this in response to
http://forums.cabling-design.com/cabling/Nordx-CDT-Troubleshooting-HELP-NEEDED-4426-.htm
 :

gseaborn wrote:




Quoted text here. Click to load it





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
http://www.cabling-design.com/homecabling/
Home Cabling Guide, Cabling Forum, color codes, pinouts and other useful
resources for premises cabling users and pros



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Re: Nordx/CDT Troubleshooting-HELP NEEDED!


Quoted text here. Click to load it

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


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