During a meeting held on February 10, the TIA TR-42.1 Commercial Building Telecommunications Cabling Subcommittee took another step closer to finalizing TIA-942-A, the revision of the TIA's data center cabling standard. Jonathan Jew, who is president of J&M Consultants and is taking a lead role in the TR-42.1 group that is revising the standard, offered some particulars about the standard's progress as well as how it will differ from the original TIA-942.
During the February meeting, the final committee ballot reached resolution, which means the specifications now move on to what is known as an industry ballot. From there it goes through a default ballot befor finally being published. Based on the timeframes in which balloting takes place, Jew said, "I expect we should be able to get to a default ballot within a year and publish sometime in 2012." The TIA TR-42 Committee meets three times per year, and some subcommittees also hold interim meetings to advance standards under development.
Jew authored an article that was published in the May 2010 issue of Cabling Installation & Maintenance magazine, providing an update on the progress of TIA-942-A at that time. Most of the changes he mentioned in that article have been incorporated into the standard's current draft. Following is a list of the major changes in the current draft of TIA-942-A.
- TIA-942-A is harmonized with the TIA-568-C standard series including the topology, terms and environmental classifications described in 568-C.0, as well as component specifications in TIA-568-C.2 and C.3.
- The addenda, TIA-942-1 and TIA-942-2, have been incorporated into 942-A; those two addenda will be superseded by TIA-942-A.
- Grounding and bonding content from TIA-942 has been removed and incorporated into TIA-607-B.
- Administration content has been removed and incorporated into the proposed TIA-606-B.
- Most content regarding cabinets/racks and power/telecommunications separation has been removed and incorporated into the proposed TIA-569-C.
- Outside-plant pathways content has been removed and incorporated into TIA-758-B.
- The 100-meter length limitation for optical-fiber horizontal cabling has been removed. Horizontal cabling distances for optical fiber are based on individual application requirements.
- Category 3 and Category 5e are no longer recognized for horizontal cabling. The draft recognizes Category 6 and Category 6A balanced twisted-pair cable types for horizontal cabling. Both types of cabling are still permitted for backbone cabling.
- The recognized multimode optical fiber cable for horizontal and backbone cabling has been changed to OM3 and OM4 850-nm laser-optimized 50/125-micron multimode fiber cable. OM1 and OM2 are no longer recognized in TIA-942-A.
- The recognized optical-fiber connectors are LC for one or two fibers and MPO for more than two fibers.
- The intermediate distribution area (IDA) has been added to the data center topology.
- An allowance for midspan powering equipment in the zone distribution area (ZDA) has been removed.
- A section on energy efficiency has been added.
- The terms "equipment outlet" (EO) and "external network interface" (ENI) from the ISO/IEC 24764 standard have been added.
A section of the TIA's home page lists "Hot Standards." The TIA-942 and TIA-568-C standards regularly occupy the top spots in the short list of such standards. Before very much longer, TIA-942-A may be atop the TIA's list of most-purchased specifications.
