OK, What am I missing????

[RandyVSP]

After alot of thought and trying to reason out some logic, I have no answer to one simple point:

Whats the big deal about deciding between the 568A and B???
I know via the pinout they are swapping the orange and brown pairs, but whats the big deal? As long as both ends are the same, I dont see where it matters......

OK, so there has to be some reason.....

Thanks for the information......

Randy

 

[joepc]

Well actually there is a very good reason why you would want to stick to the 568 B scheme. When you work with punch down panels you will see that they go by the 568 B scheme rather than A.

Now if you were doing a brand new install you use any scheme you want. But you wouldn't be following the color code on the patch panel.

But it is best to stick with the standards.

 

[jimbopalmer]

568B follows a Bell color code that predated it, 568A more closely follows USOC, and when used together they make crossover cables. that is the sum of the 'importance' of them. as JoePC says, we use them because the equipment is already set up to use a standard.

I tried to remain child-like, all I acheived was childish.

 

[RandyVSP]

To clarify, I was thinking mostly of cables, and yes, the color code and the B is my preference on punchblocks / panels

Thanks all again....

Randy

 

[Hitechbuzz]

Hi Guys
If you have equipt installed it is best to follow it. Some punch down use "A" some "B" Most of mine were done with "A" so I tend to use that one. Some "Monkeys" did an install & used "A" on patch end then "B" on outlets & did a transposition to make them work then I had to shift them (**&&%%)
Cheers
Hitechbuzz

 

[Bobg1]

Randy
A lot has to do with if you are starting a new install or adding to an existing one.
Also its the orange and green that change places, not the brown.

 

[daronwilson]

Also be aware some residential vendors (OnQ for example) provide only A products. I'd have to look, but it seems the residential specs may support 568A and not B. Most of it is personal preference really, so long as you document and do the same on both ends.

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

 

[heathbus]

You should also know that some non ATT/lucent phones and LDM's (data circuits) require 2 pairs of wires to operate and using the 568A standard makes the wiring usable without any special jumpering at either end.

 

[RandyVSP]

Thanks all....

OOPS! Yes I meant the orange and green pairs....

All of our in house stuff is B, and patch cords are A, but as long as both ends are the same, it all works...

The summation of my interest is this : There doesnt seem to be any ACTUAL difference as far as the systems go, just whatever your using, stay with it....

We use almost exclusively Sieman stuff, and really is nice having the right color codes on the blocks....

Randy

 

[jimbopalmer]

The signal in the wire cannot 'see' out of the insulation to know what color it is, all the color codes are for us humans.

I tried to remain child-like, all I acheived was childish.

 

[jeffmoss26]

That always used to confuse me, like using an A patch cable when the jacks were wired B. Someone explained that the electrons dont see the colors so as long as they are the same on both sides they will work fine.

jeff moss

 

[franklin97355]

Jeffmoss26: True as long as you keep the signal on matched pairs to keep the inductance down. If you look close the twist rate in the pairs is different and does make a difference to the quality of the signal at transmission rates.

 

[daronwilson]

Yes the twist rate is different, however it is not different enough to hamper communications on the link of 100 meters. The measurement done on the link to ensure that is delay skew, which essentially makes sure that data going down any one pair does not get to the other end faster or slower than every other pair (within the specified parameters).

That was the design anyway, and as we begin using gigabit ethernet we are using all four pairs anyway for essentially the same signal, so the delay skew is an important factor, but this tolerance is built into the specifications.

Looking back, the difference in the two pinouts came when the developed the standards. As you might have noticed there was one company already using 8 pin modular plugs for their equipment (AT&T) and they had a standard for it. That standard was included in the specifications, however the committee did not want to offer a vendor specific standard, so they came up with the other wiring code. This way they could say either was acceptable and met the standard, and not endorse one particular vendor.



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

 

[ppearce]

When the 568 Standard was originally published in 1990, the committee that was chartered with designating the wiring configuration of jacks and plugs decided upon what is known as the T568A configuration. The T568B configuration is still considered an "option" in the Standards, and as Daron noted above, is the same as the WECO (Western Electric) 258A wiring configuration.
US Federal Government publication NCS, FTR 1090-1997 recognizes only the T568A configuration.
As heathbus has pointed out above, from a strictly voice perspective, the T568A configuration sometimes offers advantages due to the fact that it has the second pair straddling the first, which allows sequential pair termination in the TR. That is to say, the positions of the first two pairs of the T568A configuration mimics the positions of the first two pairs of USOC configurations.
There is no consistent, measurable performance advantage to using either configuration.
Availability used to be a big issue, since about 90% of the installed base in North America is T568B, but with many 1st tier connectivity manufacturers now making "universally labeled" jacks and panels, that is no longer the case.
Joepc is mistaken in stating that "When you work with punch down panels you will see that they go by the 568 B scheme rather than A". Manufacturers have always made panels available in both configurations, until, as noted above, many switched to "universally labeled" products that obviated the stocking of both configurations by users.
This is more information than you want, I know. Sorry.
There's no big deal; as you stated, pick one, stick with it throughout the cable plant, and everything will be just fine. Don't worry about the patch cords, they work regardless of configuration.
Regards,
Phil Pearce, RCDD

 

[DToolsDesigner]

One final point...

The Residential manufacturers use T568A only because T568B is NOT recognized in the EIA/TIA 570-A Residential Standard.

In my company we use A only unless specified by the owner or we are adding to a job that has T568B in place already.

I find it easier for everyone to stick with one for everything, which means T568A if you do any residential work.


Richard S. Anderson, RCDD

http://www.servamatic.net

 

[PhoneGuy2000]

Good posts guys, it started splattering all ove rthe place but the last 3 posts actually wrapped it in a nice little package.