568-C.0: The next generation of cabling standards

Sept. 1, 2008
When finalized, it will become the generic document for use when a specific standard is not available, and a single repository to simplify the process of keeping standards up to date as well as speed up the development of new standards.

When finalized, it will become the generic document for use when a specific standard is not available, and a single repository to simplify the process of keeping standards up to date as well as speed up the development of new standards.

Few documents have as much effect on the structured cabling industry than the ANSI/EIA/TIA-568-B series. So, when the TIA TR-42 User Premises Telecommunications Cabling Requirements Engineering Committee says that the release of the 568-C series revisions will be released in the very near future, substantial interest is generated. In some cases, that interest is expressed as exasperation and accompanied with wailing and gnashing of teeth—usually from those folks that are finally gaining their understanding of the 568-B series!

The most common question on the 568-C crusade is, "Why are you revising the 568-B series?" The simple answer is the maximum 5-year lifespan established by the American National Standards Institute (ANSI) for standards recognized by ANSI. The first 568-C series document, 568-B.3 Optical Fiber Cabling Components Standard, was published in March 2000.

An additional consideration is the numerousaddenda that have already been published to supplement the 568-B series (for the record, six addenda to 568-B.1, 10 addenda to 568-B.2, and one addendum to 568-B.3). A revision allows these addenda to be assimilated intoone document, and addresses other advancementsworthy of consideration.

A better way

The TR-42 committee took the opportunity presented by the 568-C revision to establish a better way to develop and maintain standards. Recognizing the complications of updating several documents due to one change (for example, the release of a new Ethernet application), it makes sense to have a single repository of commoninformation rather than duplicating that information in multiple documents.

Additionally, a recurring problem is the lengthydevelopment process for creating a new standard; muchof this time is consumed by recreating and debatinginformation that is already well-established in other documents (for example, the data center standard had toinclude text on hierarchal star networks that wasalready established in 568-B.1).

Finally, the 568-B.1 standard, which was created to address office-oriented commercial buildings, has been widely used to cover other types of commercial buildings, such as airports, schools and stadiums. While this is akin to forcing a square peg into a round hole, there just was no round peg for these other types of premises—so, 568-B.1 became a de facto standard.

The solution to all of these problems was solved by creating the 568-C.0 Generic Telecommunications Cabling for Customer Premises standard. It was drafted to become the generic document for use when a specific standard is not available (for example, health care facilities), to become a single repository for common information to simplify the process of keeping standards up to date, and also to simplify and speed up the development of new standards, which can focus on the exceptions and allowances to the generic document rather than repeating generic information (this should also reduce the size and cost of new standards as well). The "568-C.0"nomenclature was chosen due to the familiarity of this nomenclature in the industry.

A foundation for standards to come

The process of creating 568-C.0 started with a complete review of all documents controlled by TR-42, which focused on extracting the repetitive and universally-applicable requirements and guidelines and moving that information into the new document (information such as choosing media, cabling lengths, polarity, installation requirements, application support tables, optical fiber testing and limits, etc.). Generally speaking, if the information was in two documents, it was considered for inclusion.

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As you may expect, much of that information was in the existing 568-B.1 document and its addenda. In fact, the current 568-B.1 document is 94 pages (not including addenda) and the draft 568-C.0 document is 60 pages with 25 pages in the draft 568-C.1 document. So, you can see this is almost an even trade as far as the number of pages are concerned, and even a reduction when the addenda pages are considered.

The 568-C.0 document is now poised to become the foundation for the other standards and for new standards that may be developed. Standards that apply to other premises, such as data centers, can focus the content on the exceptions and additional allowances to the generic standard, 568-C.0. This should make for shorter, focused documents that can be developed faster.

Additional effort was applied to get the 568-C.0 document caught up with modern times. Here are a few technical changes that are in the draft of the 568-C.0 document:

  • Installation minimum bend radius for balanced twisted-pair cable has been changed to 4x cable OD for both shielded and unshielded cable (Note: With the maximum size of 0.354 inches from 568-B.2 Addendum 11, this means the worst case minimum bend radius is now 1.5 inches for balancedtwisted-pair cable, not 1.0 inch).
  • Patch cable bend radius for balanced twisted-pair cabling has been changed to "1x cable OD" from "0.25 inches" to accommodate these larger cable diameters.
  • Maximum untwist for Category 6A cable termination was added and set to 13 mm (the same as Category 6).
  • Augmented Category 6 (Category 6A) has been added as a recognized media type.
  • Optical fiber cabling performance and testing requirements were moved to this document. (Note, however, that the copper cabling and testing requirements were moved into the draft 568-C.2 document.)

Since the 568-C.0 standard is a new document, some new nomenclature was required; existing nomenclature couldn't be used for a generic case. Although it seems like a simple concept, there was considerable debate over what nomenclature to use for the points of connection and the cabling segments. At the end of the day, "Cabling Subsystem" was used for the cabling segments, "Distributor" was chosen for the points of connection and "Equipment Outlet" was chosen for the Distributor at the end.

To address your next question, "no", the existing nomenclature in the other standards will not be changed—this nomenclature is simply new for a new standard.

What about 568-C.1?

568-C.1 is the revision to the existing 568-B.1 document, with a few important differences. First, the 568-C.1 standard is not a stand-alone document like 568-B.1. Commercial building cabling will be covered by the 568-C.0 (generic) standard, supplemented by the 568-C.1 standard (commercial building). The guidelines and requirements of 568-C.0 apply in commercial buildings subject to the exceptions and allowances detailed in 568-C.1. This allows 568-C.1 to be a focused document for office-oriented commercial buildings. Accordingly, it becomes less applicable to other premises, like schools.

As mentioned, the nomenclature in 568-C.1 does not change from 568-B.1. To tie in the 568-C.0 document with the 568-C.1 document, the following may be helpful:

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It is important to note that the requirements in 568-C.0 for the Equipment Outlet, for example, apply to the requirements for the Telecommunications Outlet in 568-C.1—as do theexceptions and allowances listed in 568-C.1. So, the two documents are necessary for office-oriented commercial building cabling.

While this may seem a bit cumbersome compared to thesingle document of 568-B.1, it is more efficient when you realize that the 568-C.0 will apply for all other premises as well.

Some technical changes to 568-C.1 were also imple-mented, including:

  • Augmented Category 6 (Category 6A) balanced twisted-pair cabling was added as a recognized media (by reference to 568-C.0).
  • A recommendation to select 850 nm laser-optimized 50/125-µm as the multimode fiber for commercial buildings is included.
  • Common information was transferred to 568-C.0.
  • 150-Ω STP cabling, Category 5 cabling, and 50-Ω and 75-Ω coaxial cabling was removed as recognized media.
  • Balanced twisted-pair cabling performance and test requirements were removed and are to be placed in the ANSI/TIA-568-C.2 document.

The component standards

Because of the similar publication dates, the component standards—568-B.2 (copper) and 568-B.3 (optical fiber)—are also due for revision. These documents, due to the development of the 568-C.0 document, were modified to become manufac-turer-focused documents.

The 568-C.3 Standard has been completed and released for publication, and the revision process allowed the incorporation of several changes:

  • ISO 11801 nomenclature (OM-1, OM-2, etc.) has been added as a parenthetical in the table of recognized fiber types.
  • Connector strain relief, housing and adapter color coding has been refined for situations when color is used to identify fiber type; however, the color codes are not mandatory in order to allow for the use of color for other purposes.
  • The minimum OFL bandwidth for 62.5/125-µm fiber was raised to 200/500 MHz•km (from 160/500). (Note: Thisapplies to 62.5-µm fibers in patch cords as well.)
  • Annex A connector test parameters have been aligned with the same parameters in the IEC 61753-1, Category C document. This means that connectors compliant to IEC would be compliant to 568-C.3. (Note: The reverse is not true, as the IEC standard includes some additional testing notcovered in 568-C.3; the IEC is the more stringent document.)

The 568-C.2 effort was competing with the 568-B.2 Addendum 10 (Augmented Category 6) effort, so it got off to a slower start. Now that the addendum has been published, the TR-42.7 committee has turned its attention to the 568-C.2 standard, with plans to publish in 2009. The first draft balloted consisted of more than 400 pages (remember that the performance and test requirements were moved into this document), but some resolved comments resulted in reducing the size down to nearly 250 pages, as some material will be moved to stand-alone documents. Interestingly enough, the TR-42.7 has already started a project to create the first addendum to the 568-C.2 standard.

Where are we today?

By the time this article is published, this information may be overcome by more recent events, since the release of some of these documents may be only weeks away. As mentioned previously, 568-C.3 has been released for publication, so it should be available by the time you read this paragraph. 568-C.2 is targeting a release near the end of 2009.

The draft 568-C.0 document was issued for its second default (limited content) ballot in June, with a ballot closing date in early August—and that may allow for a release in late August if there are no technical changes resulting from the ballot comment resolution. Similarly, the draft 568-C.1 document is out for its second default ballot, closing in early August, which may allow a release in late August as well. If not, the next scheduled meeting of TR-42 is in early October.

Just as 568-C.1 was constructed to utilize the 568-C.0 document, the remaining premise standards (residential, outside plant, data centers, etc.) will need to be revised to utilize the 568-C.0 document, too. Similarly, the other "common" standards (administration, pathways and spaces, etc.) will need to be revised to broaden their scope beyond office-oriented commercial building cabling and make them more "generic". This process has already started in some cases, and will be accomplished as these documents begin to reach their 5-year limit.

At the end of the day, probably within the next four years, the entire suite of TR-42 documents should be a complete, neat package.

HERB CONGDON is systems market manager at Tyco Electronics/AMP Netconnect (www.ampnetconnect.com), and chairman of the TIA's TR-42 committee.

TIA TR–42 is looking green

At the highest levels, the TIA has been looking for ways to use its collective expertise to address the growing interest in "green" initiatives. Specifically, TR-42 was asked to evaluate opportunities to demonstrate green leadership in the efforts and standards under their purview.

Each subcommittee provided input based on their discussions. In many cases, the subcommittees were able to point to green concepts, guidelines, and requirements that are already in place. Some examples:

Provisions in Data Center Standard (ANSI/TIA-942) are green-friendly, such as the hot and cold aisle guidelines to improve HVAC efficiency, site selection, etc.

TR-42.8 noted that fiber networks may reduce power consumption (on a per-port basis for the same application), may be constructed with less raw materials (by weight and volume) for an equivalent number of users/ports, and may be constructed with less cabling volume (for an equivalent number of users/ports) resulting in less obstruction of air flow and less impact on environmental air systems.

TR-42.1 noted that the ANSI/EIA/TIA-862, Building Auto-mation Cabling Standard for Commercial Buildings, can be used to control and automate building/facility support for such services as lighting, security, HVAC, etc.—systems that are currently recognized as being eligible for LEED credits.

Other subcommittees were able to identify opportunities in current or new projects that could be considered green:

A new project (to be Addendum 2 to TIA-942) wasstarted to expand the temperature and humidity/dewpoint ranges, allowing for lower power consumption and reduction of HVAC capacity.

TR-42.3, Pathways and Spaces, formed a new Task Group for Green Projects and started a new projects (to be Addendum 1 to TIA 569-B) on expanding the temperature and humidity requirements for telecommunications spaces, allowing for lower power consumption and reduction of HVAC capacity.

TR-42.7 is working with IEEE on pending green applications and the IEEE 802.3az Task Force on EnergyEfficient Ethernet.

It was also noted that the Leadership in Energy and Environmental Design (LEED) Green Building Rating System focuses on Divisions 1-10 of the CSI MasterFormat. Since structured cabling is covered in Division 27, there is little overlap between LEED and the scope of TR-42; however, opportunities exist for green thinking beyond LEED for structured cabling, such as using RoHS-compliant products and using pre-terminated, modular, reusable products.

Watch for further developments from the TIA as it rolls out and implements the EIATRACK program, and fromTR-42.—HC

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