One of the most popular publications coming out of the Telecommunications Industry Association (TIA) is the ANSI/TIA-942-A (American National Standards Institute). This was published in August and the following highlights of the recent changes made to the original TIA-942 standard since it was introduced in April 2005:


  1. ANSI/TIA-942-1 and ANSI/TIA-942-2 were incorporated into this standard and these two documents will be superseded at the time of publication of ANSI/TIA-942-A

  2. Grounding and bonding content from ANSI/TIA-942 was removed and incorporated into ANSI/TIA-607-B

  3. Administration content was removed and incorporated into ANSI/TIA-606-B

  4. Most content regarding cabinets/racks and power/telecommunications separation was removed and incorporated into ANSI/TIA-569-C

  5. Outside plant pathways content was removed and incorporated into to ANSI/TIA-758-B

  6. The 100-meter length limitation for optical fiber horizontal cabling was removed. Horizontal cabling distances for optical fiber are now based on individual application requirements

  7. Category 3 and Category 5e are no longer recognized for horizontal cabling. What are now recognized are balanced twisted-pair cable types for horizontal cabling for Category 6 or Category 6A.

  8. Multimode optical fiber cable is now recognized for horizontal and backbone cabling was changed to OM3 and OM4 850-nm laser-optimized 50/125-micron multimode optical fiber cable with OM4 recommended. OM1 and OM2 are no longer recognized in this standard

  9. Low count optical fiber connectors now count for one or two fibers and MPO for more than two optical fibers

  10. The Intermediate Distribution Area (IDA) was added to the data center topology

  11. The allowance for active components in the IDA was removed.

  12. Energy efficiency recommendations were added.

  13. The termsequipment outlet” and “external network interface” from ISO/IEC 24764 were added.


Essentially, the standard was simplified and reduced in size by referring to related generic TIA telecommunications infrastructure and cabling standards. The terminology was modified to match the terminology in these generic standards.

A major step to improve fiber user interfaces was the standardization of the low count connector for up to two fibers and the MPO connectors for more than two fibers at the user interface. Recognizing the need for future applications, higher performance OM4 multimode fiber is recommended in both the horizontal and backbone cabling. Similarly, for copper the standard recommends Category 6A cabling recognizing that this cabling is needed to support 10G applications.

The standard contains a wealth of information on design, installation, operation and testing of telecommunications cabling and infrastructure in data centers. It has an updated redundancy chapter that shows four tiers of redundancy in a tabular format for easy comparisons. Recognizing the high usage of multimode fiber in data centers, the standard has relaxed the distance requirements for optical fiber cabling to be based on supported applications, rather instead of the fixed 100-meter distance suited for all media types.

Based on five years of experience and feedback, ANSI/TIA-942-A is a significant improvement over the first publication of the data center standard and it is expected to remain the highest selling standard in TIA. 


If you would like to learn more about new cabling standards, I recommend you sign up for the Wednesday, October 24webinarhosted by Cabling Installation and Maintenance at 1 p.m. EDT (6 p.m. GMT). I will participate in the webinar, discussing infrastructure standards for data centers. I hope you can join us.

About the Author

Masood Shariff

Masood is an Engineer Senior Principal in the systems engineering group of CommScope. Masood represents CommScope in the ISO WG3 committee, TIA TR42 Premises Cabling Standards, including the TIA-568 series, TIA-569-C, TIA-570-B, TIA-606-B, TIA-758, TIA-862, TIA-942-A and related standards working groups. Masood served as chair of TIA TR42.7 for many years and was responsible for copper cabling systems specifications including category 5e, category 6, category 6A, and TSB-162 on WLAN cabling. Masood is currently the chair of the committee for the TIA network security project and the TIA-162 revision project. Masood has a Bachelor of Technology degree from IIT India and a Master of Science degree in Computer Science from the University of Delaware.

See all posts by this author

Add Your Comment

Please submit your comment using the form below

 
(required)