Talk:ANSI/TIA-568

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Not sure how it's happened exactly but most of this article seems to be copy-pastes of the same chunk of text? I cannot work out what's been done to it so I hope someone with more time and enthusiasm might feel like giving it a go --58.28.153.121 (talk) 08:31, 29 January 2009 (UTC)[reply]

it was some vandalism. i reverted to nov2008. mid-time revisions may have been lost though i think the only impostant thing lost is a bot task. --Gionnico (talk) 16:47, 15 February 2009 (UTC)[reply]

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]

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

Note: The old (and now deprecated) 568B pattern is illegal in US Government projects, and was from the inception of the original standard. If you're being told to use 568B, you need to bring that up as it is a violation of FISMA and NIST standards.dunerat (talk) 03:44, 24 April 2013 (UTC)[reply]

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. —Preceding unsigned comment added by 61.8.13.206 (talk) 00:13, 23 January 2008 (UTC)[reply]

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]

I also think this is a very good idea. Even though the distinction is now explained in the article. I did not fully appreciate it until reading this section. I'm not sure whether we want separate T568A and T568B articles or single T568A/T568B article. --Kvng (talk) 16:06, 25 June 2010 (UTC)[reply]

T568B has been removed from the current version of the standard, which is now TIA/EIA-568-C. dunerat (talk) 15:56, 25 October 2012 (UTC)[reply]

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]

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]

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]

---

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.

Whether or not all 8 wires are in an individual jack does not affect how easily a plug is inserted. The company i worked for often performed these types of installs for customer that wanted to save on materials costs because it cuts the number of cables you need to run in half; we called them "voice/data splits" because you would use the brown and blue pairs for the voice and the orange and green for the data, but in all cases the jacks themselves were standard 8p8c jacks. A more relevant example of what some of the other wires are used for is Power-over-Ethernet, used in VoIP applications.dunerat (talk) 04:06, 24 April 2013 (UTC)[reply]

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]

Cisco seems to think that B is most common, judging by the CCNA 3.1 material. Every new cable I've ever bought also was wired to the B standard. What does the referenced source say, and what is the basis of that authors suggestion?--itpastorn (talk) 18:18, 2 March 2008 (UTC)[reply]

According to BerkTek, B is more common in the United Stated due to it being identical to AT&T's existing wiring standard from before this standard was written and AT&T's influence on the writing of the standard is why it persisted for so long before being deprecated entirely.dunerat (talk) 03:53, 24 April 2013 (UTC)[reply]

Pushing the change - going from B to A - has created a lot of confusion. If the tiny advantage matters in an installation, one is pushing the limits and which should be corrected in other ways. This standard change should never have happened. Continue using B and life will be better. — Preceding unsigned comment added by 108.243.106.82 (talk) 19:10, 28 February 2021 (UTC)[reply]

I undid the revision of 11/13/2008, because it contradicts [1] for example. Also, it would make the standard incompatible with RJ14, so it cannot be correct. AndersJohnson (talk) 02:03, 18 November 2008 (UTC)[reply]

I've read where there are slight differences in the twists per inch between the 4 pairs of wires. If so, there will be a difference in path length between the pairs, and this can lead to timing issues when we are talking about 1000Base-T when using cat 5e cable.

Specifically, because of the path length differences between the pairs, this can have a performance consequence depending on how, for example, a wall jack is wired (568-A vs 568-B).

Does anyone know how cat-5e cable is INTENDED to be wired to obtain the performance required for 1000Base-T operation? Is it 568-A or -B ? —Preceding unsigned comment added by 74.14.82.155 (talk) 01:01, 24 November 2008 (UTC)[reply]

FTA:

Mixing T568A-terminated patch cords with T568B-terminated horizontal cables (or the reverse) does not produce pinout problems in a facility. Although it may very slightly degrade signal quality, this effect is marginal and certainly no greater than that produced by mixing cable brands in-channel.

Why would there be any speculation to any difference between an A-A cable vs. a B-B cable? Does the orange and green pigment in the insulation help signals in one direction? —Preceding unsigned comment added by 75.144.72.129 (talk) 22:55, 10 February 2009 (UTC)[reply]

Depending on the individual cable manufacturer and the grade of cable used, the mismatch in twist rate between the orange and green pairs can cause variances in NEXT, FEXT, and other problems that may cause problems, especially when multiple vendors or cabling grades are used such as during upgrades or post-construction installations.dunerat (talk) 03:56, 24 April 2013 (UTC)[reply]

From the article:

However the different pairs in an Ethernet cable are identical...

This is not true. The pairs are twisted at different rates to help prevent crosstalk between channels. I can't see many problems by swapping between pairs but transmission lines have never been my strong point. In any case, they are clearly not identical. CrispMuncher (talk) 23:06, 20 November 2009 (UTC)[reply]

The pairs are twisted at different rates to help prevent crosstalk between channels.

I can't find anything to support this. It continues to be my understanding that all 4 pairs are twisted the same, so there should be no reason to favor the orange colored pair over the green, for example. The number of twists per foot doesn't appear to be defined differently for different colors.... (Sorry, forgot to sign) 97.112.198.209 (talk) 20:13, 24 January 2010 (UTC)[reply]

The wikipedia article about Cat 5 [2] cable says that there is a different twist rate in each pair. This information is sourced from a page titled Transmission Line Zo [3] which was written by Brooke Clarke who has a masters degree in electronic engineering from San Jose State. You can also verify that the twist rate is different for each pair by examining a Cat 5 cable with the sheath removed (I know that is technically original research but I am just pointing out a way for people who doubt the referenced source to verify it for themselves). I am going to modify this section to remove the statement that the pairs are identical. Bettis211 (talk) 22:58, 4 February 2010 (UTC)[reply]

current wiring standards are:

TSB-140 Additional Guidelines for Field-Testing Length, Loss and Polarity of Optical Fiber Cabling Systems TIA-526-7 Measurement of Optical Power Loss of Installed Single-Mode Fiber Cable Plant-OFSTP-7 TIA-526-14-A Optical Power Loss Measurements of Installed Multimode Fiber Cable Plant-OFSTP-14 ANSI/TIA-568-C.0-2009 Generic Telecommunications Cabling for Customer Premises ANSI/TIA-568-C.1-2009 Commercial Building Telecommunications Cabling Standard ANSI/TIA-568-C.2-2009 Balanced Twisted-Pair Telecommunications Cabling and Components Standards ANSI/TIA-568-C.3-2008 Optical Fiber Cabling Components Standard TIA-569-B Commercial Building Standard for Telecommunications Pathways and Spaces TIA-569-B-1 Temperature and Humidity Requirements for Telecommunications Spaces ANSI/TIA-570-B-2004 Residential Telecommunications Infrastructure Standard ANSI/TIA-570-B-1 Residential Telecommunications Infrastructure Standard Addendum 1–Additional Requirements for Broadband Coaxial Cabling ANSI/TIA-598-C-2005 Optical Fiber Cable Color Coding ANSI/TIA/EIA-606-A-2002 Administration Standard for Commercial Telecommunications Infrastructure ANSI/TIA-606-A-1-2008 Administration of Equipment Rooms and Data Center Computer Rooms ANSI-J-STD-607-A-2002 Commercial Building Grounding (Earthing) and Bonding Requirements For Telecommunications ANSI/TIA-758-A-2004 Customer-owned Outside Plant Telecommunications Infrastructure Standard ANSI/TIA-942-2005 Telecommunications Infrastructure Standard for Data Centers ANSI/TIA-942-1 Data Center Coaxial Cabling Specifications and Application Distances —Preceding unsigned comment added by Eliotrobinson (talk • contribs) 15:07, 30 November 2009 (UTC)[reply]

I'm a little unconfortable with the material in this section since it confuses the characteristics of the cable itself with possible uses for it. The standards categorise performance at varying signal rates - how these translate into bandwidth is the within the scope of the relevant transmission standard as opposed to the cable specification, and with multiple pairs and/or multiple bits per symbol can be far higher than the raw signalling rate.

For example, 100BASE-T2 shifts 100Mbps full-duplex using only a 12.5MHz signalling rate over even category 3 cable, far in excess of the 16Mbps quoted, through the use of two pairs per direction and four bits per symbol. Gigabit works fine over category 5e (or even short runs of category 5) using a 125MHz signalling rate using all four pairs simultaneously for send and receive and two bits per symbol. In these cases the cable effectively "sees" a 12.5MHz or 125MHz signal - how much data that translates into is an irrelevance as far as the cable is concerned. Crispmuncher (talk) 17:40, 24 April 2012 (UTC).[reply]

Have at it. After all, ham radio operators can use a 14 MHZ carrier to send only 12 words a minute, and the relationship between data rate and signal frequency is well beyond the scope of teh standard to dictate. I don't have EIA 568 so I'm relying on idiot "pass your CNE exam" books which are truly terrible at explaining anything not on the exam. But I thought it was useful to say where the "categories" of cable were intitially defined. We should also carefully distinguish the categories as defined in TIA/EIA 568 from the various extensions and marketing terms.

Why was DC+ and DC- in the wiring diagram changed? Can the person who changed it (or anyone who knows) please reference a spec or some credible documentation which states this is the correct arrangement? The previous version where DC+ is on Blue and DC- is on White/Blue is the only arrangement I have found in web searches. Thank you Loretta who? (talk) 22:32, 2 October 2013 (UTC)[reply]

This article refers to something called a horizontal cable, but doesn't actually explain what it is. Horizontal usually means a flat, level surface. Though I would assume a riser cable that is hung in a shaft in vertical orientation between floors also qualifies as a "horizontal cable".... so the term is basically meaningless without a clear definition. -- DMahalko (talk) 13:38, 6 March 2014 (UTC)[reply]

It's been suggested that the U.S. Government's requirement for 568A, as directed in (obsolete) NIST FIPS 140, may no longer be in force. Looking for a reference. Clarkkent435 (talk) 16:28, 13 September 2016 (UTC)[reply]