what is the difference between Xbase-T and Xbase-TX?

[silverspecv]

I can't find a concise definition of the differences. They are used almost interchangably. I saw almost, because I found a lot of documentation that talks about 10base-T versus 100base-TX where they explicitly state the T and TX but never tell what the X means. The root of this question is more academic. Can 10base-TX run properly on cat3 cable? I know 10base-T does, but since I can't figure out what the X means... etc... thanks guys

 

[bcastner]

It was my niave belief that TX is to indicate that it is not T4. In any case the T stands for Twisted-pair, and the 4 or X indicates the active pairs. Since there was never to my knowledge a 10-based T4, there is no need to specify X. For 100-base T, there are two competing wiring standards, T4 and TX. TX is the most common by far.

And the answer to your question is yes.

 

[silverspecv]

So there is one and only one standard for 10mbps over copper wire? (aside from proprietary ones I mean)

 

[bcastner]

The standard specifies what are the active pairs. For 10-base T 1-2-3-6 are the active pinouts. Now there are different wiring schemes, but the practical end result is the same for 10-Base T. Pinouts 1-2-3-6 on the RJ-45 connector are used, with pinouts 1-2 on one pair, and pinouts 3-6 on the second pair.

 

[silverspecv]

I think you're right. I also think that a lot of the documentation I found today was full of errors. Stuff like saying 10base-tx runs at 100mbps for example.. I found that numerous times. Thanks for the answers!

 

[jimbopalmer]

I only know of 10baseT for ten meg ethernet on Cat 3.
99.9% of 100 meg ethernet is 100BaseTX on Cat5, but 100baseT4 on Cat3 equipment was made, it just never sold.
I am told there are two gig standards 1000baseT (UTP) and 1000baseTX (STP) but I have not messed with that

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

 

[bcastner]

Your CAT-3 runs should be fine in terms of cable quality for 10-baseT.

If well done, they likely are fine in 30 meter or so distances for 100-baseTX.

As a consultant, I specify new wire drops. But it has gotten to the point where there is so much dark cable in the walls and wiring closets that I need to rethink this. My approach is very conservative, but I think I would be happy if a TDR scan of existing Cat-5 cable pulls showed no issues, and just replacing the wallplates and the punch down blocks in the wiring closets.

It has become a lot easier to identify cables than the old days, and saving the customer a rewiring job seems sensible.