568 A/B Wiring Standards. Are they really important?

[Jayce]

I have a valid reason as to why I ask. A while ago, a friend of the family asked for my help. They had 2 computers, 1 router, 1 modem, cable connection. Computer A worked, computer B upstairs did not.

I looked at the cable and sure enough the wiring standard was off. Turns out the person who wired them was a friend of the user's network I was working on. The user + the friend worked at a telecommunications company, which they used Cat5e for their phone lines. The wiring standard was that of phones, not ethernet.

The dead-give-away was the blue wire. Clip down, the blue wire was wire 1 on both ends. I wished I had written down the exact wiring pattern on EACH end, but I just clipped them, redid the ends, and BAM. Worked.

Okay, great. So why am I bugging you guys? When it comes to patch cables, they are straight through.

What I question is this... Say I wanted to wire up my household with my own desireable wiring standard. Let's say I didn't want to wire with A or B. I wanted to do it like brown/blue/green/orange/brownstripe/bluestripe/greenstripe/orangestripe. As long as each end is wired like that, it should work... right??

 

[Greg]

Something about certain pairs being twisted together for optimal something or other...

Maybe someone who actually knows what they're talking about can fill in the rest.



EDIT - Found this on Google:

"Also, most of you probably don't know this, but there is reason for the order in 568A/568B connectors. The pairs of cables in the cable are twisted together at different ratios (called "twist ratios"). When an electrical current travels down a twisted pair of wires, a magnetic field perpendicular to the twist occurs. For ethernet, only pins 1,2,3,6 are used (the orange and green pairs). One pair is tightly twisted and the other is loosely twisted. This causes their magnetic fields to be out of synch with each other, and minimizes crosstalk. This results in much better transmission, and reduces data loss."

 

[Jayce]

Hm... but that's what I don't understand.

Pins 1 2 3 6 are used. Okay, I got that. BUT, it's straight through. So end "x" uses 1 2 3 6 and end "y" uses 1 2 3 6 with your typical 568 wiring standard, whether it's A or B.

But if I just made up my own standard and wired the ends up however I pleased, wouldn't the hybrid cable still work AS LONG AS pins 1 2 3 6 were straight-through and not crossed over at all?

Example:
568-B
orange/white(1), orange(2), green/white(3), blue, blue/white, green(6), brown/white, brown.

Hybrid-X
blue/white(1), blue(2), brown/white(3), green, orange/white, brown(6), green/white, orange.

Both 568-B and Hybrid-X have the same "straight through" ends to one another, however, just different colors. In theory, wouldn't Hybrid-X work?

 

[Ethereal_Dragon]

yes.... it would work.... but as mentioned, cross talk could be seen in the form of packet loss, and even latency... In one of my Cisco classes, a girl had a computer running really slow at work. She found the cable connected to the back of the wall jack was un-twisted for about 2 feet, and she could hardly get 10 Meg speeds over the lan, when it was a 100 Meg lan...

 

[C0RR0SIVE]

It does matter, maybe no on short runs, but you start hitting runs that go from room to room, or accross the home, it will matter, you will have packet loss, and some cable testers, can tell if the cable is actualy made right, as in using the correct standard. I do know though, if you buy a premade cable that is under 50 foot then it won't be one that conforms to standards... BTW, try running gigabit with out using the 586 standards and send a nice large 130gb file...