Talk:ANSI/TIA-568: Difference between revisions

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Diferent impedance between pairs???

The article states "The different pairs in an ethernet wire have different impedances, so an orange pair can not be connected directly to a green pair." I both highly doubt there is any significant impedance diference and have found no reference that supports it. Every page I found states that all pairs have an impedance of 100Ohms and mention nothing at all about any diference between the pairs. Ndemou 13:52, 17 July 2007 (UTC)[reply]

no title

I appreciate what has been added to clarify the 568 standards. It is a source of confusion even to the engineers to this day.
I have an observation. The standard, I believe, specifies 'blue/white w blue tracer', and I don't have those books anymore, but I believe there is some weasel words about "Similar schemes using the same colors" but in any case, of the miles and miles I have installed, I have never actually seen Solid blue, solid orange, etc. It has all been 'blue with white tracer/white with blue tracer'. It is necessary to use tracers on both wires in telco wiring based on bundles of 25 pair, since there are 5 blue wires, and white is only one of 5 background colors. I suppose Telco Wiring is another article, 25-pair color code but I think there should be mention of different coloring schemes that all use the came colors. The BISCI Telecommunications Distribution Methods Manual only recognizes the Telco 25 pair color scheme: 'Blue w White / White w Blue' first pair. (thru Violet-Slate/Slate-Violet)

Also, every design I have worked with has specified 568-B wiring, including some military projects, unless it was influenced by IBM designers. Odd, I think.

Solid Blue/white w blue tracer
Blue with white tracer/white w blue tracer
Solid blue/solid white (you have to depend on which wires are wrapped together)
Webbrewer 01:07, 13 March 2007 (UTC)[reply]

I created this page by merging the separate, but very similar articles for TIA-568A and TIA-568B, and adding additional material. Comments welcome. User:Karn 15 May 2004.

The comparison is very useful User:ahmednh

Confuses T568A/B with TIA/EIA-568A/B

This article perpetuates the commonly-held but incorrect belief that TIA-568A and TIA-568B are termination standards primarily dealing with pair/color termination.

In fact, the standards are more completely known as ANSI/TIA/EIA-568-A or ANSI/TIA/EIA-568-B and they specify all aspects of telecommunications cabling standards for commercial buildings. Subjects like topologies, cable distances, cabling types, grounding considerations, room functions and design, cable performance and test requirements are all specified in these standards.

The -B standard entirely supersedes the older -A standard.

The twisted pair termination standards referred to in this article are termed "T568A" and "T568B", and both definitions can be found within ANSI/TIA/EIA-568B. Neither termination standard supersedes the other, although the standard recommends T568A "or optionally [T568B] if necessary to accommodate certain 8-pin cabling systems." It also notes that "US Federal Government publication NCS, FTR 1090-1997 recognizes designation T568A only."

Reading this sure clears up the confusion over this unfortunate nomenclature. To assist in this effort, I have substituted the word "standard" with the word "configuration" in a few places, where this was referring to the wiring configuration T568A/T568B, rather than the standard (which currently is TIA/EIA-568-B). --- Joe.

Far less than 1% of the standard deals with termination practices.

Reference: ANSI/TIA/EIA-568-B.2-2001. April 23, 2001. 'Commercial Building Telecommunications Cabling Standard, Part 2: Balanced Twisted-Pair Cabling Components'

dpotter 19:56, 6 February 2006 (UTC)[reply]

I read over that article multiple times trying to figure out T568A and T568B. It isn't until I read your comment here that I realized what my problem is. Both T568A and T568B both redirect here. That implies that the termination standard is actually TIA/EIA-568A/B which makes further research confusing because despite the sentence that states, "These assignments are named T568A and T568B, and are frequently referred to (erroneously) as TIA/EIA-568A and TIA/EIA-568B," people make an automatic assumption that T568B == TIA/EIA-568B. People might not agree with me, but I feel that, for the purposes of those who don't have a lot of beginning knowledge on this topic, that the termination standards should be their own articles with links to the TIA/EIA-568B article. That way people can focus on reading just the T568A and T568B terminations and if more knowledge about the entire standard is required, they can continue on with a visit to the TIA/EIA-568B article. 204.147.113.35 20:45, 28 September 2006 (UTC)[reply]

Very, very good idea. I support it entirely. {{sodoit}} dpotter 01:46, 29 September 2006 (UTC)[reply]

Incorrect color codes

The color codes recently added a table and drawing are incorrect. All color/white conductors should be replaced with solid color conductors.

For example, the T568B termination standard is: white/orange, orange, white/green, blue, white/blue, green, white/brown, brown

dpotter 18:54, 14 February 2006 (UTC)[reply]

Big change

I implemented template:sofixit on this article and changed the name (preserving links to the old one). This brings the article into much better accordance with the actual subject matter of the standards under discussion, and preserved the content regarding termination methods. I relocated the Ethernet crossover cable discussion to a new article, since ethernet-specific cabling isn't relevant to the general commercial structured cabling standards (which should serve multiple communications services, of which ethernet is one). dpotter 04:53, 17 February 2006 (UTC)[reply]

The pictures showing color/white cables still are still incorrect and need to be corrected to show solid colors.

If my interpretation of 25 pair color code is correct then surely both color with white tracer and solid color are valid though admittedly in a cable with only 4 pairs there isn't much point in the white tracer and so most cable types don't include it. Plugwash 03:00, 17 February 2006 (UTC)[reply]

UTP splitters

Stuorguk:

Thanks for your edits. The description of splitter/combiner jacks was very well done. However, I think this content should be moved to another page - possibly its own page - because:

the practice is not consistent with the standard, which specifies a cable terminating at a single jack
it is specific to a small group of services (10BASE-T, 100BASE-TX) and violates one of the core goals of structured cabling - the ability to deploy any standards-based service on the wiring system.

If this content were moved, we could have a link to it from the 568B article. Perhaps something like this: Some owners of structured cabling systems choose to install UTP splitters that terminate the pairs from a single horizontal cable onto multiple jacks. This practice, while in violation of the commercial premises wiring standard, allow the combination of multiple signals on a single cable - provided that those signals use fewer that the total number of available pairs.

I've removed your content from the article, but I've included it below so it can be relocated. dpotter 00:39, 20 October 2006 (UTC)[reply]

I think i'll probablly put something about this into the ethernet over twisted pair article but first i'd like to know if there is indeed a single dominant standard for wiring theese splitters. Plugwash 18:30, 3 March 2007 (UTC)[reply]

Splitter/Combiner

Because 10BASE-T and 100BASE-TX use only pairs 2 and 3, pairs 1 and 4 need not even be present in the cable. It is also common in some networks to use one 4-pair Category 5 cable to provide two separate 10BASE-T or 100BASE-TX links, assigning only two pairs to each link. However, such jacks (sometimes called Economisers, or Splitters/Combiners) cannot be used with 1000BASE-T as it requires all four pairs for each link. They are also incompatible with direct use by single-line telephones with standard RJ11 plugs as nothing is connected to pair 1 in the jack. However, a separate telephone line could be connected to pair 1, thus allowing a single jack to be used for either voice or Ethernet without reconfiguration.

Two connections from single cable (T568B)
Pin	Connection 1	Connection 2
1
2
3
4
5
6
7
8

Whilst it is true that Ethernet systems leave 2 pairs of wires unused, they are included in the cables for 2 reasons. First, it is easier to attach a connector if all 8 wires are inserted into the conector. Secondly, these cables are not exclusively used for Ethernet use. There are other bus systems that are able to use these twisted pair cables. For example S-bus uses (IIRC) pins 1, 2, 4 and 5.

Which is more popular?

Which is more popular, 568A or 568B? I.e. which has the larger installed base? 66.170.111.2 00:31, 31 October 2007 (UTC)[reply]

I doubt anybody really knows, the parts used are exactly the same and there aren't any centralised records of which standards buildings are installed to. Plugwash 19:12, 31 October 2007 (UTC)[reply]