568A & 568B

Noe84

I have a bunch of Belkin Cat5e straight-through cables with broken tabs and I'm trying to put new connectors for them but the problem I'm seeing is which standard do I follow? These cables have TIA/EIA 568A printed on them but their color scheme matches that of the 568B standard....

I've search the Internet and can't really find out why these Belkin color scheme are that of 568B but have 568A printed on the cable. Doesn't make sense to me.

So does it really mater what color scheme I follow as long as the color match on the other end? Which would be better, because I'm assuming 568B scheme seem to be the preferred here in the USA from viewing my other cables from different brand.

KGhaleon

http://techexams.net/forums/viewtopic.php?t=23037
I asked something similar here.

Noe84

I guess it doesn't really matter as long as the color scheme match on both end. I'll just follow the T568B color scheme as it seem to be the newer standard from what wikipedia is telling me. Thanks for the link.

Netstudent

You probably already know this, but a crossover cable is nothing more than A on one side and B on the other. Straight through could be any color combination you want as long as both sides match exactly.

tech-airman

Noe84 wrote:

I have a bunch of Belkin Cat5e straight-through cables with broken tabs and I'm trying to put new connectors for them but the problem I'm seeing is which standard do I follow? These cables have TIA/EIA 568A printed on them but their color scheme matches that of the 568B standard....

I've search the Internet and can't really find out why these Belkin color scheme are that of 568B but have 568A printed on the cable. Doesn't make sense to me.

So does it really mater what color scheme I follow as long as the color match on the other end? Which would be better, because I'm assuming 568B scheme seem to be the preferred here in the USA from viewing my other cables from different brand.

Noe84,

From a standards basis, 568B is the current standard. More specifically, for copper cabling the applicable standard is 568B.2. 568A was the old standard.

As far as why Belkin used "568A" cable is because geometrically it's basically the same as "568B.2 cable." What makes a crimped cable a 568A or 568B.2 crimped cable is the color scheme used. Also, Belkin probably got a great deal on buying "568A" cabling because it's "old standard." The relatively more import number to look on the cable is the Category rating.

From a practical perspective, 568B.2 is relatively easier to deal with as far as the physical individual pairs are concerned compared to 568A. Without untwisting the pairs, see which is easier to setup for untwisting and eventual crimping, the 568B.2 or 568A arrangement? I found that 568B.2 is easier.

Now, going back to standards only a Category 5e connector + Category 5e cable = Category 5e patch cable. If you don't know if the RJ-45 connectors are rated for Category 5e, then from a standards perspective, you shouldn't get Category 5e performance from the patch cable. Then there's the issue of certifying that the crimped cable meets or exceeds the "Category 5e" standards tests. The cable testers that certifies cables and channels are usually expensive. So if this cable is intended for some sort of production network, then it's going to be cheaper to buy another certified Category 5e cable.

Does this answer your question?

Noe84

Netstudent, I just remember that actually. Thanks for the reminder.

Yes it does tech-airman and thanks.

dtlokee

568 B was the AT&T standard which came from the ATT 258A standard for RJ-11 where the center pair was the Blue pair and the the outer pins were the green pair. In theory this allowed you to wire a Cat 3 jack for dual purpose, either data or a 2 line phone. The 568 A standard is backwards compatible with the USOC standard that was widly used. When I was doing cable installs in the early 1990's all the goverment contracts required 568 A. With Cat 5 it's just a matter of what patch panel and keystone jacks you buy.

Pash

I gotta go touch a 6500 series switch at a bank tommorow, it looks like spaghetti junction in there already, i hate cables

ccnacertified2000

It is important to follow the exact standard you need. If you want to make a straight-through, use the B standard, and crossover, use A on one and B on the other end. These standards are actually important because if the cable ever needs to be punched down into a socket, those follow the coloring standards on where you put the wires. If you didn't follow the standard at the end, and you follow the colors here, then the cable won't work and you have a headache to try to figure it out.

Netstudent

GOOD POINT!

Rearden

Netstudent wrote:

You probably already know this, but a crossover cable is nothing more than A on one side and B on the other. Straight through could be any color combination you want as long as both sides match exactly.

To add to this, gigabit cables need all four pairs crossed. Both A and B have blue/white-blue have 4 and 5 unchanged in order to work with voice cabling.

Netstudent

Ya I haven't ran or cabled any CAT 6 or gigabit standards, but I hear it is different. I also heard that at these higher frequencies, Near end crosstalk is something to consider when cutting the sheath and fitting the connector.

dtlokee

All Gigabit interfaces must support auto MDI-X so you don't need crossover cables on them. May help the switch link up .0001 second faster, but not necessary.

I gotta go touch a 6500 series switch at a bank tommorow, it looks like spaghetti junction in there already, i hate cables

I would sacrifice a few shots to the cable management gods tonight to ask for their forgiveness. Good luck!