Ethernet crossover/straight through cables.

[Ren]

I am trying to help someone setup a network between two computers so they can share an internet connection. I have done this many of times and I have never had any problems doing it. I do need to get me a crossover cable before I can finish it. Well I was talking to some people on line and one of them claims to be a Network Engineer and he asked me why I was using a crossover cable. He said that he is just using a straight through cable. I have never heard of such of a thing so I asked him how he was able to do it with a straight cable. He told me that he didn't know how and his network card must be able to detect it and just be able to adapt. Now I have someone else telling mr the same thing. He said that he has never had to use a crossover cable and he had done this alot of times.

I am no expert here, I just do this as a hobby, but I have never heard of anyone connecting 2 computers together with a straight cable unless they were using a router, switch, or hub. Anyway I was wondering if anyone has ever heard of a network card that can detect if you are using a straight cable or a crossover cable and have the ability to cross it if it needs to?

[ANZAC_ELITE]

Well I'm with you, cross over has/ was / is the way to connect pc to pc.

Unless they have a dedicated nic that has some built in auto detect like most modern routers do I call BS.

Onboard ethernet ports require crossover cables in my experience.

[fiber optic]

I do network cabling for a living and I know if you use a crossover cable it will work with any 2 pc's.A straight cable will however only work between 2 pc's with new cards as new cards auto detect transmit and recieve.So if you unsure what to use a crossover is your best bet as this will work with old and new cards but not on old card and old hub.

[Ren]

Thanks guys.

I only do this is as a hobby and when someone tells me that they are an expert at something like this and tell me that they are using a straight cable but they have no idea why it works like that for them then I have to question it. Now I know that some of the new cards are capable of auto detecting it.

Cheers.

[mctoo]

Are you defining straight-through cables as *not* wired according to the the T568A or T568B standard? And how do they relate to so-called "patch cables"?

I've never used a cable that wasn't T568A or B, but at work I ran across an unused 6' Ethernet cable that had the words "patch cable" printed on it -- and the wires were straight through rather than done according to the A or B scheme. That means that signals are traveling on wires that were not paired up appropriately. Doesn't that lead to signal degradation?

I hope one of you folks can explain this to me.

[Ren]

I think patch cable could mean either or, but I am not totally sure.

A straight through cable would be wired the same on both ends. In other words, both ends would be wired as a T568A or both ends would be wired as a T568b.

On a crossover cable, one end would be wired as a T568A and the other end would be wired as a T568b.

The The data transmit and receive ports of the plug on a computer would be setup opposite of what they are on a modem or router. In this case you would need a straight through cable to allow data to flow freely.

All computers would have the transmit ports and the receive ports the same. You would need a crossover cable which crosses the wires to allow the data to flow freely.


I dont' know if I explained that clearly or very well. Like I said, this is just a hobby for me. if anyone can explain it better then by all means, please do.

[fiber optic]

Data cables are made up in pairs.
1+2 ;3+6;4+5;7+8
Not sticking to these pairs(split pairs) will lead to signal degradation due to noise.These split pair cables will work over short distance for 10mb and sometimes 100mb but never gigb as the loss over lead will be too great.