Talk:TIA-568A

TIA-568A and RJ-45 inconsistency

This part of the RJ-45 article:

“The original concept (presumably RJ11, RJ14, RJ25 and RJ61) was that the centre two pins would be one pair, the next two out the second pair, and so on until the outer pins of an eight-pin connector would be the fourth twisted pair. Additionally, signal shielding was optimised by alternating the "live" and "earthy" pins of each pair. This standard for the eight-pin connector results in a pinout known as TIA-568A, but the outermost pair are then too far apart to meet the electrical requirements of high-speed LAN protocols. The variation known as TIA-568B overcomes this by using adjacent pairs of the outer four pins for the third and fourth pairs. The inner four pins are wired identically to TIA-568A.”

seems to suggest that the normal wiring of TIA-568A should be:

1. white/brown
2. green/white
3. white/orange
4. blue/white
5. white/blue
6. orange/white
7. white/green
8. brown/white

(with pairs 2 and 3 swapped for 10/100Base-T crossover wiring), while according to the diagram in TIA-568A article it is actually:

1. white/green
2. green/white
3. white/orange
4. blue/white
5. white/blue
6. orange/white
7. white/brown
8. brown/white

which, incidently, is exactly the same as TIA-568B crossover wiring according to the diagram in TIA-568B article (and vice versa, TIA-568A crossover is TIA-568B normal wiring).

I am going to merge TIA-568A and TIA-568B articles for they differ only with the order of wires, whatever it is, but first I want to know whether the original diagrams which I have based the tables on are correct. They (the TIA-568A ones) seem to be incorrect in the context of RJ-45 article, unless the latter itself is incorrect. In any case, they both appear to be mutually contradictory and need to be corrected.

Rafał Pocztarski 07:31, 30 Jul 2004 (UTC)

Also, the RJ-45 article says:

“The variation known as TIA-568B overcomes this by using adjacent pairs of the outer four pins for the third and fourth pairs. The inner four pins are wired identically to TIA-568A.”

which is not true according to the TIA-568A diagram and table:

1. white/green
2. green/white
3. white/orange
4. blue/white
5. white/blue
6. orange/white
7. white/brown
8. brown/white

and TIA-568B diagram and table:

1. white/orange
2. orange/white
3. white/green
4. blue/white
5. white/blue
6. green/white
7. white/brown
8. brown/white

i.e. the inner four pins in TIA-568B are not wired identically to TIA-568A.

Most probably, the quoted paragraph from RJ45 is incorrect.

Rafał Pocztarski 02:54, 1 Aug 2004 (UTC)

merging TIA-568A and B

I have merged these two articles, added extra material and deleted both TIA-568A and TIA-568B and installed redirects in their place. The merged article is TIA-568A/B. Let me know what you think. User:Karn 15 May 2005.