Wiring standard A vs. B

[josephschmoe]

Have any of you ever had issues with networks wired in 568a and when a 10/100 switch was added it caused connections problems (assuming the patch panel to the rj45 wall connections are "A" on both ends)?

It has been my expierence that some switches require that everything be wired in 568b. I am of the opinion that switches(some)are wired in the "B" standard which may create a problem on an "A" wired network.

Any comments? if i am wrong or correct is there any documentation that i can view on the subject?

 

[daronwilson]

The ONLY difference between 568A and 568B is wire color. Now, if you want to really dig into it, each pair has a different twist rate which helps keep the signals from coupling to adjacent pairs. However, this difference is taken into account in the standards and testing (delay skew) and should not cause any issue.

Again the difference in the two standards is which color you transmit on and which color you receive on. No matter which you choose, we are still using the white/orange and the white/green pairs of the wire.

I have not seen any issue with using A instead of B or vice versa. I don't know of any way that the switch or hub could be wired for one standard or the other, since they are circuit board connections of a modular jack, and have no wire or wire color to deal with.

Good Luck!
It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[InnoTech]

Very true Daron!! maybe to help the explaination out a little: if both the cables (568A or B) are terminated and being used for the same kind of equiptment ie. Switch to PC, they will both work the same, as a patch cable. the color code is only for use with the cabling vendor or repair tech. just to keep up with the same code on the same job site.

Ivan

 

[rpearson]

A & B pin-outs both utilize the same ethernet pin-outs:1,2,3,6.Nothing changes.I have used 568A terminations on government and residential installations.

 

[josephschmoe]

I know that only 1,2,3,6 are constant, the problem i had experienced was very strange and maybe it was just a bad switch, or a poorly wired office, maybe even a combo of alot of things.
There is a standard for a reason. If 1+2 sending and 3+6 receiving it shouldn't matter what way you wire it as long as it is the same on both ends correct?

I think i was overthinking the situation. looking deep at emi, twists, etc.
Enough rambling... time to go home..

thanks for the input!

 

[InnoTech]

yep, you're correct. if the pin-out's the same, it's a patch cable.

 

[Bobg1]

Everyones told him that a vs b makes no difference.
So the question comes down to why does he have problems when changing a switch.

Joseph
It could be the wiring, it could be the switch settings, it could be the nic setings.
Since it sounds like you had a network running prior, we can assume it was at 10. Try hard setting the switch ports at 10 and see if they work (they should).
Now if you want to run at 100 you first need to make sure your nics are capable, if they are you probably have to reset them to do so, then you can also set the switch the same.
You should be able to get it functioning at 100 if you are able to get it going at 10.
Now if it seems to work but not that well at 100 you probably have cabling issues.

 

[OMBD]

We're not talking about anything as old as LattisNet are we?
As stated in several of these post, it should not have made any difference. You purchase patch panels, inserts, etc. in 568A or 568B configurations but I've not seen a switch being designated A or B. The post referring to the NIC cards may be the way to start. Make(buy) a reverse cable and at the patch panel go from one PC to another PC(no switch involved or other NIC's)and see if 100Mbps is possible. We do this sometimes with a laptop directly at the patch panel. If you can not get 100Mbps here by this method then don't look for the switch to help or be of any concern. Jerry Pannell

http://www.SCLB.com

techs@sclb.com