TIA 942 was published in 2005 and has been recently updated to 942-A with a variety of changes. Most notable changes include the removal of category 3 and 5e for horizontal cabling (they are allowed for voice backbone only now), and an incorporation of 942-1 and 942-2 making 6A the minimum recommended category of copper cabling in a data center. On the fiber side of the equation, OM4 is now the minimum recommended grade of fiber. The MTP/MPO connector is the only approved connector for multi-strand fiber, and LC is the preferred connector for two strand.
There is a new section on energy efficiency as well which recommends proper pathway planning to eliminate some of the issues that happen due to neglect. Top of Rack switching is not mentioned as it is a point to point connection rather than a structured connection, but it does include language that any point to point cable MUST be removed when it is no longer in use. This may be tricky in some data centers over time, but it is a requirement.
Much of the Uptime Institute information in the informative annex has either been stricken or updated due to changes since the original inclusion. It is important to note that there is NO such thing as a TIA Tier level anything as, by definition, anything contained in the informative annex is not part of the standard. The only mention of Tiers in the main body of standards is the suggestion that for high tier facilities that the primary and secondary cables take disparate pathways.
The 568 series is now a link in this standard as opposed to dual language in both. The same is true for 569, 606, 607 and 758.
A new area called an intermediate distribution area is also included for larger data centers and colocation facilities. This optional area sits between the main distribution area and the horizontal distribution areas.
For a copy of the standard and its contents, you can visit www.tiaonline.com
