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@$#@$#@#$ Network Cabling
slinga - May 7, 2003
  slinga May 7, 2003
Ahhhhhhhhhhhhhhhh stupid network cables driving me insane.

I ran a new cable from my router to my sister's computer. It won't work. It was a straight-through cable and it won't light up the linksys ports. I swapped out the network card with another one still nothing. I visually check the wires and everything looks ok. I plug it into a tester and everything tests ok. Any idea what I'm doing wrong? Could the connectors be a factor? I'll post up the model number of the connectors I'm using, but they look like standard rj45. The cable is Gigabit, could that be the problem? I was under the impression that Gigabit cable was backwards compatible with 100 megabit cards. Meaning you could run the higher grade cable, just without any speed gains. Is this correct? If not I'm going to beat the people at Home Depot's ass (hey there networking shit was cheaper). Maybe I'm crimping wrong? What's the "correct" way to crimp a wire?

Also how do I wire a crossover cable? I checked on google, couldn't find a good guide. Thanks in advance.

 Curtis May 7, 2003
Gigabit cable (cat 5e? 6?) should be fine for 100Meg transmission. It could be that the router is picky about the correct wiring standard (i.e. the right colours going to the right pins) although I would think that unlikely. You say the cable checks out with a tester, which would suggest the cable is actually fine. All I can suggest about crimping is to do it firmly - you need quite a bit of force to get the wires in properly. Just make sure none of them have jumped into another track.

Have you considered that the router may be at fault?

I'll try to find the Cisco guide for wiring up crossover cables for you.

 mal May 7, 2003
This... might tell you what you want to know about crossover cables.

You could try replacing a working cable from the router to another PC with the suspect one and see if it works or not. That should narrow it down to the cable rather than any other hardware.

 spoonx0r May 12, 2003
What router are you using. Model Number? What else is plugged into it? And what ports are they plugged into?

 slinga May 18, 2003
What does it mean if the lights keep flashing? I've determined that problem is indeed my cable. I've recrimped it a couple of times, I don't know what could be causing the problem. The lights just keep flashing, on my laptop it keeps going back and forth from being connected to being disconnected.

 mal May 18, 2003
Did you try swapping the suspect cable with a known 'good' cable?

That will tell you straight away if the cable is the problem.

 Taelon May 19, 2003
He already said he'd plugged the cable into a tester and it was fine.

I do wonder, though, HOW LONG THE CABLE IS... might it be there's a limit on gigabit cable lengths?

 mal May 19, 2003
If it's fine then why does he keep recrimping it?

To save a hell of a lot of time and hassle, just go and buy one.

That way you should know if it's the cable or not, and if it isn't, you can rule the cable out and concentrate on the other potential issues.

 Taelon May 19, 2003
Good point, I don't know how I missed that one (about recrimping it).

 Curtis May 19, 2003
Technically, you can't have a twisted pair ethernet cable longer than 100m. If you follow the TIA/EIA standards (I think it is these standards) to the letter, then the cable you are running shouldn't be longer than 90m. I really don't think this is a problem.

 slinga May 20, 2003
I think there are multiple things wrong in my network. To try and pinpoint the error, I plugged the cable into a working router port (the one I normally use), and connected the cable to my laptop, which I know which works for a fact. No dice. The lights kept connecting and disconnecting on both the laptop and the router. I then plugged a known-working cable into the same port. Voila it works. Why not just use this cable? I need to run about 50 feet of cable, hence why I decided to make my own.

There's only one thing I think I'm messing up now, the pin colors of the wire. As it is now, there in the same order on both ends of the wire (Color - Color white so on). Someone in school told me that the order of the color pairs matters. I highly doubt that, but at this point I will try anything. (what's another connecter, I've gone through about 20 already....).

And thanks for all your ideas guys, I really appreciate it.

 Curtis May 20, 2003
The color pairs really do matter - especially when you are running longer lengths of cable. The pairs are grouped in a manner which reduces electrical interference (or crosstalk) between the individual wires inside the cable. Each pair is twisted a different number of times, and that has the effect of canceling out quite a bit electrical interference. If you start messing with the order, you begin to get problems.

 slinga May 21, 2003
Yep you guys were right. Color pairs do matter. Everything works great now. Man I feel stupid. Thanks guys.