| Author |
Message |
Robert Redelmeier
Guest
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 Posted:
Sun Apr 24, 2005 11:01 pm Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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gaudetteje@gmail.com wrote:
| Quote: | the 3' untwisted cable with crimp connectors does not give
me a link light when I plug any NIC or hub into either end.
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Of course not. Flat silver satin does not provide the
necessary pairing (twist) for noise isolation.
I have made flat cable work for 15m at 10baseT by using
USOC order to give a small measure of noise (crosstalk)
isolation. But I don't believe such tricks work for more
than inches of 100baseTX.
If you cannot replace the cable by some twisted Cat5e
because of your water"proof" connectors, you might try
re-allocating conductors (breakout boxes/custom cables).
This project is worth real money, and it is probably for
getting a Pentascanner or equivalent certification tool in
to check your links. You won't make spec, but at least
you wioll get an idea of what is "least bad".
-- Robert |
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Dale Farmer
Guest
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| Posted:
Sun Apr 24, 2005 11:05 pm Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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gaudetteje@gmail.com wrote:
| Quote: | If I can't reduce the noise in the waterproof cable we have, then this
would be our only other option, though _no_ water is acceptable as we
will most undoubtedly fry the equipment if the power shorts in certain
places. We have lots of gunk to plug up the hole as long as we can
keep tension off of it.
|
Sealing around the cable isn't going to be your leakage problem.
The jacket of the cable isn't intended for watertightness, just for
physical protection. Something you could try is to take a section
of cat 5 cable, carefully strip away the outer jacket from a section,
and then you have the four individual twisted pairs accessible to
be packed into a sealing gland. Then terminate outside the
pressure hull with a regular ( corrosion resistant! ) modular plug,
which you can then plug in a regular cat 5 cable. Put that whole
jack and plug into a pressure compensated oil bath to keep the
water out of the connector.
| Quote: |
As with any project, of course it needs to be working by tomorrow
morning so switching to fiber isn't an option (yet). I will keep that
in mind for later on if we still have the need to be tethered.
Accoustic communications has been done many times before, but we don't
have the equipment now.
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I'd push hard for going to optical fibers. They are way more durable
in a water environment.
--Dale |
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Guest
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| Posted:
Mon Apr 25, 2005 4:00 pm Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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I found that the untwisted cable actually works with the 30m of UTP
after many revisions. What I had to do was twist the individual wires
coming in from the bulkhead, which consisted of about 1 foot of the 3.
I also had to remove all of the butted crimp connectors, since the
impedance changes must have been causing severe reflections to distort
the signal. Instead, I simply soldered the pins together where they
meet. I'm also going to try using some header and socket pins that can
mate together. Those hopefully won't add much noise, but will be
stronger than solder links.
Thanks for everyone's help, it definately helped me to get this
working.
Jason |
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jgolan
Guest
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| Posted:
Tue Apr 26, 2005 12:20 am Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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Your color coding to pins is incorrect and inconsistant....follow the
information in this link for the proper sequence to use with either
10BaseT or 100BaseT ethernet
http://www.cabling-design.com/references/pinouts/10-100base_t_crossover.shtml
Due to the 3' un paired cable you may not achieve 100BaseT but you should
be able to squeeze out 10BaseT
Joe Golan, RCDD
-------------------------------------
gaudetteje@gmail.com wrote:
| Quote: | Since this may be part of the problem, I should explicitly indicate how
my cables were inserted into each RJ-45 jack.
Pin Jack A Jack B
1 w/o w/bl
2 o g
3 w/bl w/o
4 bl bl
5 w/g w/g
6 g o
7 w/br w/br
8 br br
I'm assuming these may not match the specifications and thus I don't
have proper shielding from the twisted pair. I also still suspect the
crimp connectors may be causing unwanted reflections in the network
traffic.
|
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Mark Evans
Guest
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| Posted:
Wed Apr 27, 2005 3:31 pm Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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gaudetteje@gmail.com wrote:
| Quote: | Hi,
I'm having a CAT5 network cabling issue and am fresh out of
troubleshooting ideas. The cable is a CAT5 stranded cable, which I
made to be about 100 feet long. Each end uses an RJ-45 connector and I
made the cable a crossover cable to connect two NICs directly (pins 1-3
and 2-6 were switched on one end). Due to the application
requirements, at one of the ends I have another 3 feet of 8-wire cable
inserted, which has a slightly larger gauge. To interconnect these 3
pieces of cable, I have an 18-22 AWG butted crimp terminal on each
|
Where does the third piece of wire come from.
The crimps are intended for telephone circuits. They are not suitable
for LAN cables.
| Quote: | Here's the problem: When I plug my network cable between two machines
(or a hub and one of the machines), I get a link light and activity,
but cannot get an IMCP ping response nor can I get get a response via
SSH. I have no problems when I use a similar CAT5 crossover cable that
is only 3 feet long. According to the hub, I have activity on the
port, but I haven't been successful in communicating over the 100'
cable.
|
The "activity" may be the speed auto-negotiation. You'd be lucky to get
even 10M down a cable in such a state.
| Quote: | There are 2 different reasons I can think of that may be causing the
problems. The first is that even though CAT5 is specified to work up
to 100 meters (about 300+ feet), maybe my signal is losing it's
|
It's 100 metres with solid core cable.
| Quote: | integrity due to the length of the cable (this is definately a long
transmission line) and the connectors I had to insert near one of the
ends. The second theory is that since my cable is coiled up on a desk
and the fact that I have a long transmission line, my signal is losing
its integrity due to crosstalk noise from the signal's delayed version
of itself.
|
If it's coiled on a desk why do you need to bodge another metre or so onto
it?
If you really have to join the cable use either a CAT-5 junction box,
trailing female RJ-45 or RJ-45 coupler.
--
Mark Evans
St. Peter's CofE Aided School
Phone: +44 1392 204764 X109
Fax: +44 1392 204763 |
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Mark Evans
Guest
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| Posted:
Wed Apr 27, 2005 3:37 pm Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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gaudetteje@gmail.com wrote:
| Quote: | I'm going to split my completed cable into 2 parts. The first part
will just be CAT5 twisted pair at about 30m and the second will be the
2 feet of untwisted large-gauge wire with crimp connections to CAT5
|
Why do you want to do this?
| Quote: | cable on either side. I'd expect to see that one works fine and the
other does not to help me troubleshoot.
|
With this length of untwisted cable about the only thing you could do
with the link is put one (four it you didn't mind the crosstalk issues)
telephone line down it.
You really can't expect it to work if you don't use the correct cable.
--
Mark Evans
St. Peter's CofE Aided School
Phone: +44 1392 204764 X109
Fax: +44 1392 204763 |
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James Knott
Guest
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| Posted:
Wed Apr 27, 2005 3:50 pm Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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Mark Evans wrote:
| Quote: | With this length of untwisted cable about the only thing you could do
with the link is put one (four it you didn't mind the crosstalk issues)
telephone line down it.
|
Phone crosstalk??? In such a short cable??? Your phone line, back to the
CO, is run for a far greater distance, without noticeable crosstalk. |
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Mark Evans
Guest
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| Posted:
Wed Apr 27, 2005 4:20 pm Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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gaudetteje@gmail.com wrote:
| Quote: | I was incorrect when I said the cable was stranded... My 30m or so of
cat5 cable is actually solid. It is the 2 feet of untwisted cable that
is stranded.
|
You don't really want to use soild core in such an application. The
crimp connectors are unlikely to work reliably if you treat it as
flex.
| Quote: | James:
The application that requires me to do this is to have a water-proof
connector to the hull of a submersible vehicle. Rather odd
application, I admit... However, the ethernet connection is necessary
for controlling the vehicle at this stage. The waterproof 8-pin
connector I have to work with is by Subconn.
The specific model I am using is the Micro 8 (MCBH8F & MCIL8M):
http://www.subconn.com/subconn.asp?page=cir15&pic=img2f
I understand that the cable is non-spec for ethernet communications,
but I don't really have an option at this point. Is this strictly a
noise issue? Should I try minimizing the noise from the connectors by
replacing them with a solder connection? I can also reduce the size of
|
This would be a good place to start, solder the cat5 directly to
the 8 way plug and socket. Be careful not to untwist the pairs any
more than you need to.
| Quote: | the cable as a last resort; however, once I cut the cable I don't have
a backup.
|
--
Mark Evans
St. Peter's CofE Aided School
Phone: +44 1392 204764 X109
Fax: +44 1392 204763 |
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Guest
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| Posted:
Thu Apr 28, 2005 12:20 am Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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James Knott <james.knott@rogers.com> wrote:
| Quote: |
Phone crosstalk??? In such a short cable??? Your phone line, back to the
CO, is run for a far greater distance, without noticeable crosstalk.
|
Yes, but it's twisted pair.
-Larry Jones
Oh yeah? You just wait! -- Calvin |
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James Knott
Guest
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| Posted:
Thu Apr 28, 2005 7:09 am Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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lawrence.jones@ugs.com wrote:
| Quote: | James Knott <james.knott@rogers.com> wrote:
Phone crosstalk??? In such a short cable??? Your phone line, back to
the CO, is run for a far greater distance, without noticeable crosstalk.
Yes, but it's twisted pair.
-Larry Jones
|
The flat "satin" cable used for phones isn't twisted either, nor is that
"quad" stuff that was standard for phone installations for many years. I
don't see that 3 feet of untwisted cable will cause crosstalk. |
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Mark Evans
Guest
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| Posted:
Thu Apr 28, 2005 2:50 pm Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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James Knott <james.knott@rogers.com> wrote:
| Quote: | Mark Evans wrote:
With this length of untwisted cable about the only thing you could do
with the link is put one (four it you didn't mind the crosstalk issues)
telephone line down it.
Phone crosstalk??? In such a short cable??? Your phone line, back to the
CO, is run for a far greater distance, without noticeable crosstalk.
|
Telephone cable is still UTP.
The only exception is some single
pair cables.
--
Mark Evans
St. Peter's CofE Aided School
Phone: +44 1392 204764 X109
Fax: +44 1392 204763 |
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James Knott
Guest
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| Posted:
Thu Apr 28, 2005 4:02 pm Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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Mark Evans wrote:
| Quote: | Phone crosstalk??? In such a short cable??? Your phone line, back to
the CO, is run for a far greater distance, without noticeable crosstalk.
Telephone cable is still UTP.
The only exception is some single
pair cables.
|
He was referring to crosstalk in a 3 foot piece on untwisted cable.
However, for many years, premise phone wiring was done with untwisted pair
cables. Even on today's modular phone, the flat satin wire is not twisted.
Cables going back to the CO is twisted pair, but not as tightly twisted as
cat 3 or 5. |
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Guest
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| Posted:
Fri Apr 29, 2005 12:20 am Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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James Knott <james.knott@rogers.com> wrote:
| Quote: |
The flat "satin" cable used for phones isn't twisted either, nor is that
"quad" stuff that was standard for phone installations for many years.
|
Those aren't run "back to the CO", either. Satin isn't used for any
significant distance because it does have significant crosstalk
problems. Quad, on the other hand, doesn't have much immunity from
external noise since it's not twisted, but it has excellent immunity
from crosstalk because the molded jacket holds the pairs such that the
signals induced in one pair by the other exactly cancel each other.
-Larry Jones
OK, what's the NEXT amendment say? I know it's in here someplace. -- Calvin |
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Ed Nielsen
Guest
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| Posted:
Fri Apr 29, 2005 6:28 am Post subject:
Re: Troubleshooting a 100' CAT5 cable - need assistance |
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lawrence.jones@ugs.com wrote:
| Quote: | Satin isn't used for any
significant distance because it does have significant crosstalk
problems.
|
I had a 25' satin cord for awhile on which I ran 2 lines. Crosstalk up
the ying-yang. And that was when the phone at the end of the cord was
on line 1 and the phone at another outlet was on the line 2. Finally, I
got un-lazy enough to run a real outlet where it was needed to get rid
of that satin. Problem, of course, went away.
CIAO!
Ed N. |
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