Did you ever wonder why the "holy grail" for telecommunications structured cabling, TIA-568, always seems to be changing?
Did you know that ANSI mandates that standards be revised, withdrawn or reaffirmed every five years? This review usually begins with a "wish list" and ends with publication of a new document—or, in this case, a series of documents.
If you have been in the business awhile, you may remember the original ANSI/EIA/TIA-568-1991 Commercial Building Telecommunications Wiring Standard. Believe it or not, work on that document started in 1985.
Yes, the original TIA-568 took six years of meetings, debates, ballots, debates, discussions, debates ...well, I think you get the idea. But the importance of this document was that it established the "structure" for what we call structured cabling.
The structure of the structure
TIA-568-1991 was followed by publication of:
- TSB36-1991—Additional Cable specification for Unshielded Twisted Pair Cables;
- TSB40-1992 and TSB40A-1994—Additional Transmission Specification for Unshielded Twisted Pair Connection Hardware.
These gave us Category 3, 4 and 5 cable and connector descriptions.
After only four years in the re-making, ANSI/TIA/EIA-568-A-1995—Commercial Building Telecommunications Cabling Standard was published. TIA-568-A absorbed the information in TSB36 and TSB40A, giving us the first TIA standard with Category 3, 4 and 5 component requirements.
TIA-568-1995 was followed by publication of:
- TSB67-1995—Transmission Performance Specifications for Field Testing of Unshielded Twisted Pair Cabling Systems, which gave us some idea how to test and see if what we were installing was what we were paying for.
- TSB72-1995—Centralized Optical Fiber Cabling, which introduced the concept of not having to cut a perfectly good optical-fiber cable in to segments and install a bunch of termination shelves and connectors in the TR—just because it went through the TR.
- TSB75-1996—Additional Horizontal Cabling Practices for Open Offices, which introduced consolidation points (CPs) and multi-user telecommunications outlet assemblies (MUTOAs).
- TSB95-1999—Additional Transmission Performance Guidelines for 4-Pair 100-Ohm Category 5 Cabling, which described what to do to make the cabling that we had installed do what we thought it would do when we installed it—mitigation procedures.
And then there was the parade of addenda:
- TIA-568-A-1997 Addendum 1, Propagation Delay and Delay Skew Specifications for 100 Ohm 4-pair Cable, which refined the copper cable specification.
- TIA-568-A-1998 Addendum 2, Corrections and Additions to TIA/EIA-568-A.
- TIA-568-A-1998 Addendum 3, which addressed hybrid and bundled cable.
- TIA-568-A-1999, Addendum 4, Production Modular Cord NEXT Test Method and Requirements for Unshielded Twisted-Pair Cabling, which told manufacturers how to test the patch cords they were selling.
- TIA-568-A-1999, Addendum 5, Transmission Performance Specifications for 4-pair 100-Ohm Category 5e Cabling, which finally "drove the stake in the ground" for Category 5e cabling.
So, by the TIA-568-B edition, "the structured cabling thing" had gotten so big, they divided it into three parts:
- ANSI/TIA/EIA-568-B.-2001 Commercial Building Telecommunications Cabling Standard—Part 1: General Requirements, which was primarily for designers, installers and end users.
- ANSI/TIA/EIA-568-B.2-2001 Commercial Building Telecommunications Cabling Standard—Part 2: Balanced Twisted Pair Cabling Components, which was primarily for manufacturers.
- ANSI/TIA/EIA-568-B.3-2000 Optical Fiber Cabling Components Standard, which was primarily for manufacturers.
TIA-568-B—the miniseries—absorbed the information in the five TIA-568-A addenda plus TSB67, TSB72, TSB75 and TSB95 and the lesser-known TIA-IS-729-1999 Technical Specifications for 100-Ohm Screened Twisted-Pair Cabling.
In addition, TIA-568-B series made some significant technical changes that affect the way we designed, installed and used structured cabling:
- Performance specifications were provided for 50/125-µm optical fiber and cables;
- In addition to the 568SC, small-form-factor optical-fiber connector designs were allowed;
- The permanent link has replaced the basic link as a test configuration;
- Minimum bend radius and maximum pulling tension was provided for horizontal and backbone cable.
But wait, there's more
And then the addenda procession began anew:
- TIA-568-B.1-1-2001 Addendum 1—Minimum 4-Pair UTP and 4-Pair ScTP Patch Cable Bend Radius;
- TIA-568-B.1-2-2003 Addendum 2—Grounding and Bonding; Requirements for Screened Balanced Twisted-Pair Horizontal Cabling;
- TIA-568-B.1-3-2003 Addendum 3—Supportable Distances and Channel Attenuation for Optical Fiber Applications by Fiber Type;
- TIA-568-B.1-4-2003 Addendum 4—Recognition of Category 6 and 850-nm Laser-Optimized 50/125-µm Multimode Optical Fiber Cabling;
- TIA-568-B.1-5-200? (pending) Addendum 5—Telecommunications Cabling for Telecommunications Enclosures;
- TIA-568-B.1-6-200? (pending) Addendum 6—Additional Cabling Guidelines for DTE Power;
- TIA-568-B.2-1-2002 Addendum 1—Transmission Performance Specifications for 4-Pair 100-Ohm Category 6 Cabling;
- TIA-568-B.2-2-2001 Addendum 2—Corrections to TIA/EIA-568-B.2;
- TIA-568-B.2-3-2002 Addendum 3—Additional Considerations for Insertion Loss and Return Loss Pass/Fail Determination;
- TIA-568-B.2-4-2002 Addendum 4—Solderless Connection Reliability Requirements for Copper Connecting Hardware;
- TIA-568-B.2-5-2003 Addendum 5—Corrections to TIA/EIA-568-B.2;
- TIA-568-B.2-6-200? (pending) Addendum 6—Category 6 Related Component Test Procedures;
- TIA-568-B.2-7-200? (pending) Addendum 7—Reliability Specification Requirements for Copper Connecting Hardware;
- TIA-568-B.2-8-200? (pending) Addendum 8—Additional Component Requirements for DTE Power;
- TIA-568-B.3-1-2002 Addendum 1—Additional Transmission Performance Specifications for 50/125-µm Optical Fiber Cables.
More TSBs, too
The TIA has also been busy developing new TSBs:
- TSB125-2001 Guidelines for Maintaining Optical Fiber Polarity Through Reverse-Pair Positioning;
- TSB136-200? (pending) Guidelines For Maintaining Optical Fiber Polarity With Systems Utilizing MPO Connectors;
- TSB140-200? (pending) Additional Guidelines for Field-Testing Length, Loss and Polarity of Optical Fiber Cabling Systems;
- TSB153-200? (pending) Static Discharge Between LAN Cabling and Data Terminal Equipment.
And now, 568-C
Given the current "body of knowledge," pending publications and the previous timeline from "wish list" to publication, it is time to start work on 568-C.
It does not require a crystal ball to predict what TIA-568-C will absorb: all the addenda. Probably TSB125, TSB136, TSB140 and TSB153 will also find their way into TIA 568-C series. But then what? The committee will begin reviewing their "wish list," of course.
Some ideas on the current "wish list" include:
- Extending the 90-meter pull-through limit on centralized optical-fiber cabling to 300 meters, eliminating the requirement for a splice of interconnect in the TR;
- Color coding optical-fiber jackets and connectors to avoid intermating of different fiber types;
- Adding references for indoor/outdoor optical-fiber cables.
If you have a few ideas of your own to add to the "wish list," forward them to TR-42 Chair, Bob Jensen (firstname.lastname@example.org), and he will send them along to the appropriate subcommittee for consideration.
It won't be long now
Something to think about...
- TIA-568 era gave us Categories 3, 4, and 5;
- TIA-568-A era gave us Category 5e;
- TIA-568-B era gave us Category 6.
Which begs the question: Will the TIA-568-C era give us yet another generation of copper cabling to install? And will it be a new "gee-whiz Category 6" (they cannot just call it Category 6e; manufacturers are already marketing CAT6e and CAT6E), or Category 7, or both?
We will likely not have to wait very long to know. The current application to support is 10GBase-T. IEEE plans to decide the media requirements for 10GBase-T at their November meeting.
Donna Ballast is BICSI's standards representative, and a BICSI registered communications distribution designer (RCDD). Send your questions to Donna via e-mail: email@example.com