568A and 568B wiring question

Joined
Jan 24, 2002
Messages
686
Wanted to ask before I either changed everything or keep it the same. I have multiple cat5e runs in my house. The ones I wired are the 568B standard. The ones that the builder did before I bought the house are 586A standard. My question silly as it is...

Most patch panel cables are 568B. Will I have any issues plugging a normal patch panel 568B cable into the patch panel that have some wired as 568b and 568a?

IE: Each outlet has two rj45 ports. One is wired 568A, the other beside is 568B. Those two go all the way down to my network closet which I have wired into a patch panel. Again, same wiring at each end so the 568A is that on both ends, and 568B is that on both ends of the cable (not mix matched). If I needed to run a patch panel cable from one port that was wired 568A to a 568B port using the standard 568B patch panel will there be any issues, IE: no communication on that line?

For some reason I think I am getting this mixed up with a crossover cable, which it's not, the pairs would still be the same, unlike the cross over cable where it wouldn't be...

Just wanted to confirm before I either cut all the ends off the builder wire to do it 568B standard and purchasing new connectors ... or if it's all good?


EDIT: Actually more specifically after I wrote it down. The ports that are wired at the 568A standard and into the patch panel. Will there be any problem plugging a normal 568B patch panel cable to the port on the switch with the port on the patch panel?

Made this crappy diagram... hopefully it helps better explain how some is wired.





Thanks,
-Nigel
 
Last edited:
Joined
Dec 1, 2011
Messages
819
It'll be fine. The connector pinouts are identical between the two standards, it's just some minor differences in what colors go where.

Though I don't understand why you used 568B at a location that had existing 568A wiring.
 

rma

Limp Gawd
Joined
Mar 16, 2015
Messages
200
Fast response :)

NO there won't be any problems mixing 568A and 568B.
 

rma

Limp Gawd
Joined
Mar 16, 2015
Messages
200
to get technical

the difference is of the way of the twisting in the cable, they changed it to 568B because of a little better noise immunity, therefore new wiring should be 568B, but as BlueLineSwinger said it's more convenient to just keep running the standard that all ready is in use.
 
Joined
Jan 24, 2002
Messages
686
It'll be fine. The connector pinouts are identical between the two standards, it's just some minor differences in what colors go where.

Though I don't understand why you used 568B at a location that had existing 568A wiring.
Everything I do is the 568B standard, never the 568A. So when I started terminating the ends naturally I started doing all B. I haven't use A in such a long time that when I first looked at how it was wired in my house I was like they did it wrong...lol Call it old habit I guess but I just don't like the 568A, when I think of wiring things up it's always 568B. I have labeled everything so anyone that comes after me or I die will be able to follow exactly what was done..lol

Appreciate all the info guys! At least I know I won't have more work to do :)

-Nigel
 

GotNoRice

[H]F Junkie
Joined
Jul 11, 2001
Messages
9,640
568A on one end and 568A on the other represents a normal connection.
568B on one end and 568B on the other represents a normal connection.
568A on one end and 568B on the other (or vise versa) represents a crossover connection.

Crossover connections (or cables) used to be used for things like connecting two computers together directly, or connecting two switches or hubs together, where normal cables were just used for connections between the computer and the switch/hub. But for the last 10-15+ years pretty much everything has been auto-crossover. Auto-crossover is actually built into the gigabit spec, so anything that is gigabit is automatically auto-crossover. What that means in practice is that you can use 568A or 568B interchangeably in absolutely any situation and it doesn't matter in any way. Even if you have some ancient 10 or 100mbit devices that can't handle auto-crossover themselves, as long as it's auto-crossover on the other end it won't matter.
 

Grentz

Fully [H]
Joined
May 5, 2006
Messages
17,150
Frankly these days it does not matter much. Just make sure you use one of them. I have been on plenty of jobs using A and plenty using B and not noticed any performance differences. One advantage of A in residential is that it is wired the same as a 2 line phone jack.
 

QuiteSufficient

Sufficiently [H]ard
Joined
Mar 2, 2001
Messages
5,148
Where are you located?

It is my understanding that B is used pretty exclusively in the US (what I always use) and that A is largely used elsewhere.
 

Grentz

Fully [H]
Joined
May 5, 2006
Messages
17,150
Where are you located?

It is my understanding that B is used pretty exclusively in the US (what I always use) and that A is largely used elsewhere.
Not necessarily. It more depends on the original intent of use. I see a lot of video and phone installers prefer A while general network cablers tend towards B
 
Joined
Jan 24, 2002
Messages
686
Sweet appreciate it! I'm in Virginia.

So after crimping the connector and punch down to one of the rooms I get zero indicator lights... I'm pissed cause it's in the bedroom so running a new cable is out of the question unless I start ripping drywall up. I did use a tone tool on the one cat5 run and it rings through on both ends...

I am thinking that somewhere in the run the cable is broke but I wanted to make sure. Any problem with hooking a 9v battery up to two of the wires in the cat5 at the patch panel and then using a multimeter to check the other end (then keep switching -/+ and checking the other 3 pairs of wires?). I figure doing so will at least give me a reading on if it's a broken wire somewhere... at best I could always then re-wire and use different pairs instead of the normal wiring, at worst the entire cable is bad and then I just live with it..

Thanks,
-Nigel
 

jeffmoss26

2[H]4U
Joined
Aug 1, 2002
Messages
2,267
I always use B unless matching existing. I will say that A makes it easier to use 2 phone lines or a 2 pair digital phone with 4 pair cable since the blue and orange pairs are in the same positions as USOC.
 
Joined
Jan 24, 2002
Messages
686
Forgot to update. So everything is working great. Even terminated the outside line coming in so I can call Verizon and have them switch their ONT box to Ethernet rather than Coax since I don't want to use their router anymore.

The one cable I thought was broke earlier isn't. I ended up buying a Fluke Microscanner2 and it showed that the line from the basement was 52', then when I measure from the bedroom indicated it was 19', so clearly there was a disconnect or broken spot somewhere.

I go up to the attic and found the feed, the idiots who build the house had used electrical tape to join the cat5e cable from the wall to the main feed.... smh.

I got two jacks, terminated it and then joined the cable together. Tested and works perfectly! w00t w00t!
Would explain why my 9v or checking other pairs weren't working from my cheaper tester. Everything works great. Some are wired A that were the phone lines, and all my new ones that I terminated are B. Everything is great now. A shame they didn't do this right when they built the house but that's ok, it's done now and now I can enjoy it.

-Nigel
 

Lunas

[H]F Junkie
Joined
Jul 22, 2001
Messages
9,876
As long as both ends of all cables and connections are the same there is no difference.

A standard has the green pair first instead of the orange b standard uses the orange pair as the first 2 so green on both ends when you put in a b-b standard the orange connects exactly the same as the green so pins 1 and 2 remain pins 1 and 2 a cross over is when you swap them on the other side so pins 1 and 2 terminate to 3 and 6 on one end and 1 and 2 on the other.

All 4 pairs are used in gigabit.
and the blue pairs are positive and brown are negative in most poe
 
Last edited:
Top