T568A or T568B
- Thread starter MStan
- Start date
upstatemike
Senior Member
The only difference is where the the white/orange and white/green pairs get placed on the plug or jack. These are the only 2 pairs used in 10/100 ethernet and they swap positions when moving from T568A to T568B. I use T568A because it places the white/orange pair right next to the white/blue pair in the jack. This helps me because my phone system uses white/blue and white/orange so I can re-task any jack from data to phone very easily at the cross-connect blocks. Apart from that there is no benefit that I am aware of.
drozwood90
Senior Member
I've always done B...
Mostly because I started wiring before I knew there was a standard. I copied another cable I had, which was B.
Now I just do it because it's what I can remember.
I also will point out a little more clearly what was stated above. Not ONLY does it swap the 10/100 cables, but by crimping one end B and one end A, you end up with a crossover cable for 10/100 (I'm not positive about 1000 as I'm just getting into it!).
It's also helpful that I'm doing B around my house...since the builder pre-punched a bunch of connectors in my house, and it just so happens that they did B, which made me happy, as that's what I use!!!
Beyond that, there's not advantage. The big thing was to try to determine a crossover standard (so my guess is that it is a crossover for 1000bt as well, but I do not remember).
--Dan
Mostly because I started wiring before I knew there was a standard. I copied another cable I had, which was B.
Now I just do it because it's what I can remember.
I also will point out a little more clearly what was stated above. Not ONLY does it swap the 10/100 cables, but by crimping one end B and one end A, you end up with a crossover cable for 10/100 (I'm not positive about 1000 as I'm just getting into it!).
It's also helpful that I'm doing B around my house...since the builder pre-punched a bunch of connectors in my house, and it just so happens that they did B, which made me happy, as that's what I use!!!
Beyond that, there's not advantage. The big thing was to try to determine a crossover standard (so my guess is that it is a crossover for 1000bt as well, but I do not remember).
--Dan
Ya, no terminations were done in my house at all, so I got to choose! I chose A because it is far superior to B.
Yeah, but if A is so good, then why did they come out with B at all? B must be better than A... it's like cable termination 2.0.
Which reminds me of one of life's very important questions. What ever happened to the people who tested Preperations A-G?
Brett
Photon
Active Member
Ya, no terminations were done in my house at all, so I got to choose! I chose A because it is far superior to B.
Yeah, but if A is so good, then why did they come out with B at all? B must be better than A... it's like cable termination 2.0.
Which reminds me of one of life's very important questions. What ever happened to the people who tested Preperations A-G?
Brett
The story I like is that the EIA/TIA settled on T568A, but AT&T already used a different standard, 258A. They wouldn't sign off on the standards unless the industry recognised theirs, which is now known as T568B.
I wire my house to T568B because I mess with it at work and I don't want to use both. Besides, I occasionally find useful devices in the, er. . . trash can at work.
felixrosbergen
Senior Member
Is there problems when you do it one way or another??
If you termnate the same way at both of ends of the cable run does it matter then?
What if i terminate one way on a quickport and put a RJ45 connection on the other side?
This stuff has me so confused...
If you termnate the same way at both of ends of the cable run does it matter then?
What if i terminate one way on a quickport and put a RJ45 connection on the other side?
This stuff has me so confused...
This is the same reason why I use A. It has come in handy more than once.
Besides, all the cool guys use A.
Mark
mustangcoupe
Senior Member
Always terminate it the same way.... otherwise it wont work. Transmit and receive lines will be all messed up and no linky linky
which also means no communications!
I use B also. Most of the customers I have seen in the past 10 years use B. Seems to be the most common.
If you terminate B on the quickport then wire the RJ-45 as B be and you'll be fine. I have several temporary connections made in my house like this.
A on one end and B on the other is a crossover cable.
If you use B in your cable runs at both ends and you buy patch cables that are A you are also fine. As long as the cable pairs don't cross between any 2 wired connection points . (Quickport to Quickport or patch cable end to patch cable end)
Here is what always has me confused:
In order for the connections to work using the consistent A or B orientation throughout does the cable always need to have the same connector at each end? In other words in does the cable always need to have a plug at both ends or a quickport at both ends? If you have a cable with a plug on one end and a quickport on the other and both are, lets say, A, does that create a cross-over?
robolo
In order for the connections to work using the consistent A or B orientation throughout does the cable always need to have the same connector at each end? In other words in does the cable always need to have a plug at both ends or a quickport at both ends? If you have a cable with a plug on one end and a quickport on the other and both are, lets say, A, does that create a cross-over?
robolo
BraveSirRobbin
Moderator
I'm not in IT and don't do this very often, but I had the situation where I had to run a Cat5e line for a office wall outlet, then terminate the other end into an existing patch panel (inside the data room). The panel in this very old building had no indications on it as to if it was wired as an "A" or "B" (only one set of colors on the "sides", not two like a connector has).
What is the best way to tell? Just count the colors and see where the orange/white and green/white colors line up in relation to the other colors? I couldn't open up some existing outlets to see how they were wired.
I was in a terrible hurry (long story but it had to do with getting this done before any "IT" types walked in) and just used the equation A = Old, B = New(er) and wired the connector end as A and guessed right.
What is the best way to tell? Just count the colors and see where the orange/white and green/white colors line up in relation to the other colors? I couldn't open up some existing outlets to see how they were wired.
I was in a terrible hurry (long story but it had to do with getting this done before any "IT" types walked in) and just used the equation A = Old, B = New(er) and wired the connector end as A and guessed right.