TIA Specification Will Address Greater-Than-100-Meters Over Twisted Pair

The Telecommunications Industry Association’s (TIA) TR-42 Telecommunications Cabling Systems Engineering Committee will tackle the topic of supporting more than 100-meter distances over twisted-pair copper cabling. The TR-42.7 Engineering Committee on Telecommunications Copper Cabling Systems recently issued a call for interest, which officially kicks off the process of developing a standard document. The document will be Telecommunications Systems Bulletin (TSB) 5073, tentatively titled “Guidelines for Supporting Extended Distances over 4-Pair Balanced Twisted-Pair Cabling.”

When issuing the call for interest, the TIA said it is “actively seeking participation in this process from the user and general interest communities,” and that “stakeholders may include but are not limited to cable and connectivity manufacturers, test equipment manufacturers, installers/integrators, [and] end users.”

A TSB is not the same type of document as a TIA standard in that a standard includes what are called “normative” specifications, meaning they are requirements. TIA standards may also include what are called “informative” sections, meaning that following these specifications is not required in order to be standard-compliant; these informative sections can be viewed as guidance rather than requirements. A TSB document as a whole can be considered informative; it includes guidance, recommendations, and best-practice information.

The TIA has published numerous TSBs to deliver best-practice guidance to professionals who design, install, and manage information and communications technology (ICT) systems. Some of the TSBs most relevant to cabling systems include the following.

• TSB-6000 Application Channel Attenuation and Supportable Distances
• TSB-162-B Telecommunications Cabling Guidelines for Wireless Access Points (currently being revised to a “C” version)
• TSB-190-A Guidelines on Shared Pathways and Shared Sheaths
• TSB-184-A Guidelines for Supporting Power Delivery Over Twisted-Pair Cabling
• TSB-5018 Structured Cabling Infrastructure Guidelines to Support Distributed Antenna Systems

The issue of running twisted-pair cabling beyond 100 meters, and using that cabling for the transmission of data and DC power via Power over Ethernet, has been a frequently discussed topic within the ICT industry for a couple years. TIA standards limit twisted-pair cabling channels to 100-meter maximum length, including up to a 90-meter permanent link and up to 10 meters of equipment and work-area cords.

Multiple cable manufacturers have introduced products that, when terminated to standard-compliant connectivity, will support data transmission beyond 100 meters. In many cases, a properly installed channel greater than 100 meters in length that includes these cables will pass the channel test for a given performance level. Yet the channel will not be standard-compliant because it exceeds the 100-meter limit. Complicating the matter is that many twisted-pair cabling product manufacturers stipulate that their warranties are valid only if the installed products/systems are standard-compliant—meaning a channel that is more than 100 meters is not warranted by the manufacturer.

The timeline for the publication of a TSB within the TIA, from call-for-interest to completed document, typically can be measured in months. We will continue to follow the development of TSB-5073 and report to you on its progress.