Cabling Problems

Wakar · 21-11-2005, 09:58

Hi All,

firstly just to explain my setup before explaining my problem. I currently have a Server, Desktop Machine and a laptop the server, desktop and laptop are all hard wired into a cable router (linksys BEFSR41)that currently runs to the NTL 2MB BB connection. I want to use the laptop downstairs at times and so I wanted an internet connection there too.

In my previous jobs at IT Technician in primary schools one the kind schools gave to me a box of 305m of connective cat 5e cabling

. so i thought i could use this cabling to extend network downstairs. After measuring the length of cabling I crimpped the RJ45 modules onto each end and tried connecting. this is where my problem comes in.

it keeps on looking to obtain IP address and in the end it gets a 169.x.x.x address. however when i try to connect the the laptop upstairs it works fine.

the cables are crimmped in the following ways:

orangewhite - orange - bluewhite - blue - greenwhite - green - brownwhite - brown, and this is the same at both ends.

I have also tried:

orange - orangewhite - green - greenwhite - blue - bluewhite - brown - brownwhite, at both ends.

but this still does not seem to work. anyone have any ideas i cud try b4 stirpping out the cable and trying a new one. Also have tried wireless but not too keen i get a bad signal. 15% signal strength.

thanks in advance
wakar

Aragorn · 21-11-2005, 10:30

Waqar,

Never tried making patch cables myself, but a quick google pulled up http://www.lanshack.com/make-cat5E.asp which looks like a good guide to cabling up an rj45 cable.

HTH

Wakar · 21-11-2005, 10:39

thanks for that, i did see that after i posted on here. The funny thing is that all my home cabling i have made myself and they all seem to work fine except this one. will double check everything again to night and decide where to go from there.

Regards
Wakar

SMHarman · 21-11-2005, 11:12

When it gets the 169 address can you log onto the router to see that the DHCP server has given an address to the laptop.

Does ipConfig give what you expect back?

Sounds like a cable is damaged in the run, this does not necessarily mean a repull as CAT5 only uses 4 of the 8 cores, can you circuit test all of the wires to see if any are broken?

As long as the pairs are kept paired they can be in any order as long as they are in the same order at both ends, so if you find a the blue pair damaged, you could swap the brown and blue pairs to get a good connection from the cable.

What are the ping results if you ping your router? Are you losing lots of packets?

Wakar · 21-11-2005, 12:08

will have to try this when i get home later this afternoon, will post results then..

hayesey · 21-11-2005, 14:29

at the end of the day it doesn't actually matter what order the wires are crimped in a cat5 cable as long as both ends as the same (for a straight through cable anyway). Have you got a cable tester you can use to see if each contact on the rj45 at one end is connected to the corresponding wire at the other end? You could even use a multimeter to test this. How long is the cable you've made? If it is more than 100metres then it's not going to work well if at all. When you connect the cable up do you get lights on the network card & the router?

A "169" IP address means that DHCP failed. Are you able to get into the router from another PC on the network, is there anything in the log file(s) on there which might suggest why your PC isn't getting a DHCP lease.

Graham M · 21-11-2005, 16:25

the order of the wires at the plug end DOES matter, as the Pairs are twisted in a certain way for it to work. If you want a straight through, wire the following at each end.

Either:

Orange-White Orange Green-White Blue Blue-White Green Brown-White Brown

Or:

Green-White Green Orange-White Blue Blue-White Orange Brown-White Brown

The first wiring order is the most well used, if you want a crossover cable, wire one way at one end and the other way at the other end.

HTH.

SMHarman · 21-11-2005, 17:07

However on a particular cable you could also wire

Blue Blue-White Green-White Orange-White Orange Green Brown-White Brown

And as long as you do that at both ends you get the same straight through cbale, though it is not wired to any known wiring standard. But if your Orange cable was damaged you could subst with blue.

Though Blue and Orange are the primary two pairs, so you will find you need to swap in the green and brown pairs.

SMHarman · 21-11-2005, 17:14

http://www.swhowto.com/WhatWant.htm
http://web.ukonline.co.uk/freshwater/rj45.htm
http://www.homestead.co.uk/productca...tegoryid=51025

Links I found useful when I structured cabled a small office. That is running voice and data over the structure.

Graham M · 21-11-2005, 17:24

Its Orange and Green that are used surely as those are the pairs you swap when writing a crossover.

SMHarman · 21-11-2005, 17:27

Yes, if only 7 of the wires in the 8 work though, rather than replace the cable, if one of the orange or green wires is damaged, you could swap that pair in that cable with the blue or brown, then the data on that cable would be say orange blue and with 4 working wires you would have a working cable.

I'm badly explaining a 1 off fix here, not how to wire up a screwed up cat 5 cable.

GeoffW · 21-11-2005, 21:16

Nobody has asked the obvious question - how long is the cable? 100m is the maximum distance you get.

A 169 address means no connection to the DHCP server so its definitely at lower layers. Do you get a carrier? Can you see packets in and out of the status icon?

SMHarman · 22-11-2005, 00:01

Unless his name is bill gates, you will struggle to run a 100 m path from upstairs to downstairs of any house. IMHO.