T568A or T568B?
Scott Presnell
I'm making some progress in setting up a home ethernet via UTP lines.
I've come to realize that there are two wiring specifications 568A and 568B
that I could use in choosing hardware, wiring jacks, etc.
My understanding is that 568B (AT&T) is the original specification but
"it is recommended" that new installations use 568A.
I'm leaning towards 568B just because it's been around longer and seems
to be in common use.
Can anyone provide me with a solid reason for which specification I should
choose in setting up my home/office ethernetwork?
(If this is an FAQ somewhere, please point me in the appropriate direction).
Thanks for your time.
- Scott Presnell (s...@zgi.com)
Mike Daniel
As long as you use the same scheme at both end of a wire, it doesn't
matter which scheme you use. As I've read many time, the electrons don't
know the color of the insulation.
568B is more common in older installations in the USA. 568A is more
common in Europe and is preferred by the official EIA/TIA 568-A wiring
spec.
I'd go with 568A because the spec recommends it. It will probably come to
dominate and they may one day REQUIRE 568A. Then you're ahead of the
game.
Mike
--
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J. Clarke
and works on it who isn't particularly up to speed they'll assume 568B.
Outside the US go with A. From a functional viewpoint there's no difference
as long as everything is wired to the same spec.
--
--John
Reply to jclarke at eye bee em dot net.
Scott Presnell wrote in message <363BC75E...@zgi.com>...
Wolfgang Rupprecht
> I'd go with 568A because the spec recommends it. It will probably come to
> dominate and they may one day REQUIRE 568A. Then you're ahead of the
> game.
The method I used to choose was to see which ones were more stocked.
It appeared to me that the B's were always in stock. As silly as it
sounds the bulk cable that I have is marked "568B". (Is there really
any difference in "A" or "B" cable, such as twist rates changing
slightly so that the fast/med/slow/realslow twists stay on the same
pairs?)
When it was essentially a coin flip anyway, the "B" won.
-wolfgang
--
Wolfgang Rupprecht <wolf...@dailyplanet.wsrcc.com>
http://www.wsrcc.com/wolfgang/
Cut down on spam. Install ORBS support: http://www.dorkslayers.com/orbs/
Stephen W. Jones
(pairs 1 & 2) follow the color code scheme for telephones, thus, if you
now or in the future have 2 phone lines it might make it easier to
follow....
take a look at the bottom of this page
http://www.teleport.com/~tmate/howcable.htm
Timothy Iafolla
cable. However, I usually go with 568A, because the middle 6 wires are
color coded and arranged the same as a USOC6 3-pair phone jack. This makes
it easy to re-designate a computer line as a phone line, just by patching to
a different device (phone block vs hub) without rewiring the jack. Hope
this helps,
Timothy Iafolla
Home Information Networks, Inc.
301-926-6505
Scott Presnell wrote in message <363BC75E...@zgi.com>...
Eugene Nine
different. They do keep pairs paired between the two standards too, so it
doens't matter, but the 586b stuff is easier to find sometimes. I was able
to find jacks from mouser electronics that can be wired either way, and six
jack wall plates so I can wire ethernet, phone, cable, etc.
Eugene
Wolfgang Rupprecht wrote in message ...
pe...@petrocelli.com
Scott Presnell <s...@zgi.com> wrote:
> Hi Folks,
> I'm making some progress in setting up a home ethernet via UTP lines.
> I've come to realize that there are two wiring specifications 568A and 568B
> that I could use in choosing hardware, wiring jacks, etc.
>
> My understanding is that 568B (AT&T) is the original specification but
> "it is recommended" that new installations use 568A.
>
> I'm leaning towards 568B just because it's been around longer and seems
> to be in common use.
>
> Can anyone provide me with a solid reason for which specification I should
> choose in setting up my home/office ethernetwork?
>
> (If this is an FAQ somewhere, please point me in the appropriate direction).
>
> Thanks for your time.
>
> - Scott Presnell (s...@zgi.com)
>
As so many other have expressed, it really doesn't matter to data as long as
you stay with one scheme. However on of the other replies stated that they
like 568A because it matches USOC for three pairs....this is incorrect it
only matches the first two pairs and is helpful if you will be using two line
telephone sets that use USOC pinning (normal).
--
Best regards,
Joe Golan, RCDD
Director of Telecommunications
Petrocelli Communications
LIC, NY
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Jeff Kell
>
> FWIW, if you're in the US go with 568B. Reason is that if someone comes in
> and works on it who isn't particularly up to speed they'll assume 568B.
> Outside the US go with A. From a functional viewpoint there's no difference
> as long as everything is wired to the same spec.
I agree. In the US, T568B is more common, being an AT&T spec. The
T568A spec started with Northern Telecom in Canada. But as others have
pointed out, the pairings come out the same either way, only pairs 2/3
(pins 1,2,3,6) are swapped between the two. From an end-to-end view it
makes no difference unless someone is punching down a new cable on one
end and 'assuming' the wiring code is one of the two on the other end.
As long as both ends agree what standard is in effect, it makes no
difference whatsoever except what color wires are used on either end.
Jeff Kell <jeff...@utc.edu>
Chris Bischoff
for RJ-14 connections (2-lines). Given that, I'm curious why AT&T came
out with the T568B wiring scheme. Anyone know?
Chris Bischoff
Brian Karas
jacks. And with neither scheme can you use Ethernet _and_ 2 lines on
the same cable, not that I recommend this anyway....
[] [] Chris Bischoff <bisc...@ix.netcom.com> was saying:
>I agree with you. Using T568A scheme allows the RJ-45 jacks to be used
>for RJ-14 connections (2-lines). Given that, I'm curious why AT&T came
>out with the T568B wiring scheme. Anyone know?
>
>Chris Bischoff
--
Brian@ 'at' @Karas. 'dot' .com.
Return address munged to prevent SPAM...
SOHO DataComm wiring, FAQ's, etc:
http://www.PhysicalLayer.com
Kevin Oberman
> I agree with you. Using T568A scheme allows the RJ-45 jacks to be used
> for RJ-14 connections (2-lines). Given that, I'm curious why AT&T came
> out with the T568B wiring scheme. Anyone know?
The only difference between 568A and 568B is the color of the
insulation on 4 of the wires. Anything that works with 568A will work
with 568B as long as both ends are wired to the same standard. It
does not matter a bit if half of the cables were 568A and half
568B. But, when both ends are not visible, having mixed standards is
asking for trouble.
In the US I would stick to 568B, but always check for existing wiring
match it if it is present.
As far as I know, AT&T came out with its standard before NT did the
opposite. But in international standards bodies, politics is the key
and every country has one vote. AT&T probably had to work like crazy
to get 568B into the spec at all.
--
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: obe...@es.net Phone: +1 510 486-8634
Tom Nemeth
for the 2 "variants" is that you need to allow for a cross-over cables (eg.
cascading hubs, etc) and for the whole cabling system to be certified, ALL
termination sequences must be as per the standard. It is nothing to do with
politics (well, not as much as normally), just a matter of not leaving gaps.
In my understanding, T568B is the "normal", and T568A is the "cross-over".
Tom Nemeth
--
In article <sreyapn...@ptavv.es.net> Kevin Oberman <obe...@es.net>
writes:>From: Kevin Oberman <obe...@es.net>
>Subject: Re: T568A or T568B?
>Date: 07 Nov 1998 12:54:14 -0800
Brian Karas
it's just that the orange and green pair change places from one spec
to the other.
Cross-over cables are actually non-standard. Most hubs have an MDI
port built into them, or else use a proprietary cascading method.
Little 4 and 8 port hubs may not have a cascading or uplink system
built into them and require the use of a crossover cable, but these
are rarely used to make a large network.
568B is more 'normal' in the US, 568A is more normal in Europe.
[] [] tne...@camtech.net.au (Tom Nemeth) was saying:
>Yes, what you all say is correct, but you are missing the point. The reason
>for the 2 "variants" is that you need to allow for a cross-over cables (eg.
>cascading hubs, etc) and for the whole cabling system to be certified, ALL
>termination sequences must be as per the standard. It is nothing to do with
>politics (well, not as much as normally), just a matter of not leaving gaps.
>In my understanding, T568B is the "normal", and T568A is the "cross-over".
>
>Tom Nemeth
--
Kevin Oberman
> Yes, what you all say is correct, but you are missing the point. The reason
> for the 2 "variants" is that you need to allow for a cross-over cables (eg.
> cascading hubs, etc) and for the whole cabling system to be certified, ALL
> termination sequences must be as per the standard. It is nothing to do with
> politics (well, not as much as normally), just a matter of not leaving gaps.
> In my understanding, T568B is the "normal", and T568A is the "cross-over".
I'm afraid not. You are confused, and it seems so are many others.
Once again, there is NO DIFFERENCE between 586A and 586B except for
the color of two pairs. Neither is a "cross-over". Technically,
cross-over cables violate the spec, be it A or B.
Eugene Nine
cables and crossover cables are actully interchangable (at leat for now)
since 10/100 ethernet still uses two pair and those two pair are in the same
place (even if they are a different color set) You can evey get away with
using straight modular cord for patch and swap one end for crossover (it
will probably add a lot of noise). But anyway whatever standard you follow
you need to make 568a patch cables and crossover cables, or make t568b patch
or crossover cables.
Eugene
Tom Nemeth wrote in message ...
>Yes, what you all say is correct, but you are missing the point. The
reason
>for the 2 "variants" is that you need to allow for a cross-over cables (eg.
>cascading hubs, etc) and for the whole cabling system to be certified, ALL
>termination sequences must be as per the standard. It is nothing to do
with
>politics (well, not as much as normally), just a matter of not leaving
gaps.
>In my understanding, T568B is the "normal", and T568A is the "cross-over".
>
>Tom Nemeth
>--
>
>In article <sreyapn...@ptavv.es.net> Kevin Oberman <obe...@es.net>
>writes:>From: Kevin Oberman <obe...@es.net>
>>Subject: Re: T568A or T568B?
>>Date: 07 Nov 1998 12:54:14 -0800
>
>>Chris Bischoff <bisc...@ix.netcom.com> writes:
>a
The Multimedia And Technology Examiner
are referring to the fact that the patch cables [such as used between a LAN
hub and a patch-panel going to the station wire] will work for either
specification. That much is true. A Category 5 patch cable will work for
either the 568A or 568B specification. If you look at both ends of the
cable on a normal Category 5 patch cable, you will see that the colors are
identical in the modular plug. They are wired straight-through.
You are also correct in saying that the entire facility should be wired to
the same specification.
The only difference between 568A and 568B is in where pairs 2 and 3 appear
on the 8-position 8-conductor modular jacks used throughout the system. It
is more than just the color of the pair. Those colors correspond to
physical positions on a jack.
On a punch block the pair colors are....
BLUE - ORANGE - GREEN - BROWN
P1 - P2 - P3 - P4
This is a standard. You use the same blocks for 568A and 568B. They don't
care. Pair 1 is always blue, pair 2 is always orange, etc. But, where do
each of these pairs appear on the jacks?
A 568A jack has pair 2 straddling pair 1, and pair 3 is to the left. 568B
reverses this [pair 3 straddling pair 1, pair 2 is to the left]. Again,
patch cables are wired straight through, so they don't care. But the jacks
are different.
568A pair scheme on 8 pins: 33211244
568B pair scheme on 8 pins: 22311344
As long as the same scheme is used in the facility, LANs are fine. But,
what about host equipment that is pair-specific.
The Lucent Definity/System 75 have the ability to use older 2-pair digital
terminals. These use pair 2 and pair 3 of the 568B specification. The host
equipment expects that it will be connected to pair 2 and pair 3 [568B] at
the jack. These are polarity sensitive.
Let's also look at the example of a simple key system [such as the BBS
Telecom IPS-416] which wants pairs 1 and 2 of the USOC specification. Pairs
1 and 2 of the 568A specification are identical to the USOC specification.
In the case of the Definity, if you have wired the facility as 568B, you are
fine. Cross-connect the PBX port to the pair 2 and pair 3 positions on the
punch-block that goes out to the station cable.
But what if you have used the 568A specification? Since pairs 2 and 3
appear at different positions on the 568A jack [reversed from 568B], you
need to cross-connect the PBX port backwards. In other words, connect the
PBX port to pairs 3 and 2 on the punch-block. That's because the 568A jack
has pairs 2 and 3 appearing in different positions at the jack.
On the IPS-416 system, it expects to see pair 2 straddling pair 1. That's
USOC or 568A. If the facility is wired 568B, you need to cross-connect the
PBX to what appears to be pairs 1 and 3 on the punch-block. Again, because
568B has the pairs in reversed positions as compared to 568A.
I hope that clears things up for those users interested in the differences.
-- James Bell Jr. -- Editor - THE MULTIMEDIA AND TECHNOLOGY EXAMINER -
http://www.teleport.com/~tmate
Kevin Oberman wrote in message ...
alex...@gmail.com
> In article <363BC75E...@zgi.com>, s...@zgi.com says...
> > I'm making some progress in setting up a home ethernet via UTP lines.
> > I've come to realize that there are two wiring specifications 568A and 568B
> > that I could use in choosing hardware, wiring jacks, etc.
> >
> > My understanding is that 568B (AT&T) is the original specification but
> > "it is recommended" that new installations use 568A.
> >
> > I'm leaning towards 568B just because it's been around longer and seems
> > to be in common use.
> >
> > Can anyone provide me with a solid reason for which specification I should
> > choose in setting up my home/office ethernetwork?
> >
> > (If this is an FAQ somewhere, please point me in the appropriate direction).
> >
> > Thanks for your time.
> >
> > - Scott Presnell (s...@zgi.com)
> >
>
> matter which scheme you use. As I've read many time, the electrons don't
> know the color of the insulation.
>
> 568B is more common in older installations in the USA. 568A is more
> common in Europe and is preferred by the official EIA/TIA 568-A wiring
> spec.
>
> dominate and they may one day REQUIRE 568A. Then you're ahead of the
> game.
>
>
> --
> **************************
> My reply-to is Anti-spam
> True username is mdaniel
> **************************