Sign in with
Sign up | Sign in
Your question

Can't get Cat5e cable to work

Last response: in Networking
Share
July 27, 2009 11:42:44 PM

Hi,
I've recently bought a router and some cable to connect both home computers to the internet via a cable modem. One is a WinXP, one is a Slax (the one of concern).

Now I've never before attached the endings to the cable myself, but this time I needed to since I cannot drill a hole in the wall big enough to pull the ending thru (that's a factor I cannot change). After a few attempts, I've created attached both ending so that both the router says and the Slax' network card LED are on (not blinking, which is good at least for the router, as the manual says and it would blink before).

Now, I can't get the Slax computer to get online. The router saw the computer for a few minutes, but it would only lease the IP address from the router's DHCP for 1 minute (with the preset being 24 hours, as the well behaved WinXP machine does), and after those few minutes, it wouldn't show on the router's DHCP clients list anymore. Even during those few minutes, the computer wouldn't ping the router or resolve DNS (I didn't try any external IP address, if that would be of help). dhcpcd eth0 always times out.

I've also tried bringing the slax to the other room and it works with a bought cable, so that rules out OS/drivers. Sadly, I can't check the cable as it's too short and thru the wall and I understand all testers need both ends of the cable to be plugged in (obviously). I also believe I have mastered the crimps quite well by now and guess that shouldn't be a problem (the cable I've attached endings to has the same wire configuration as the bought one (straight one, not twisted, I believe).

Now, I know there's probably not much more to do, but does anybody have any idea what to try next? Any way to test the cable using two computers (some diagnostic program maybe?), anything? Sorry, I'm just desperate and running out of solutions.

More about : cat5e cable work

July 29, 2009 5:26:01 AM

Hi,
thanks for the answer... I've followed a youtube video and the result looks like http://en.wikipedia.org/wiki/File:Cat_5.jpg (brown, brown stripe, green, green stripe, blue, blue stripe, orange, orange stripe). This differes from both T568A and T568B. If you suspect the problem might be due to some interactions ("crosstalk") due to the green pair not being separated by the blue pair (as per T568B), I'll try and reattach the plugs (I'll try today and let you know).

Related resources
July 29, 2009 6:00:34 AM

Well, you are a saviour, I've done it T568B way and it works! Sincere thanks for pointing that out, really helped a lot! :hello:  I owe you a beer or something... :) 

As a bonus, would you mind explaining why this works, while the read-made cable's wire arrangement (as mentioned in the previous post) doesn't?
July 29, 2009 11:05:07 AM

It didn't work because one pair is on pins 3 and 6 and another pair is on pins 4 and 5. Since you wired them incorrectly, transmit and receive signal for 2 pairs was split across 2 pairs and that caused enough crosstalk to make the cable useless.

The link that you provided has the wiring correct. The image isn't perfect, but you can see a green wire on pin 6, a white/green wire on pin 3, a white/blue on pin 5 and a blue wire on pin 4.
!