Issue link: https://www.e-digitaleditions.com/i/1156106
October/November/December 2019 I 43 susceptibility of the affected systems in order to maintain an acceptable level of interference. An acceptable level is defined as an amount of steady-state or surge induced longitudinal voltage or current that does not cause a personnel or public safety hazard, damage to cable or equipment, and/or circuit degradation or failure." While the document is intended more for communi- cation service providers (CSPs), the information is applicable to LANs. In 1991, IEEE standard 1137, Guide For The Implemen- tation of Inductive Coordination Mitigation Techniques and Application, was published. In December 2018, it was also updated along with its new title, Recommended Practice for the Implementation of Inductive Coordination Mitigation Techniques and Application. 9 Its scope states that "This recommended practice offers users assistance in con- trolling or modifying the inductive environment and the susceptibility of affected wire-line telecommunications facilities in order to operate within the acceptable levels of steady-state or surge-induced voltages of the environ- mental interface (probe wire) defined by IEEE Std 776." IEEE 1137 discusses the application and operation of an INT but not in a LAN environment. It is important to note that the remaining standards that are mentioned do not discuss the problems caused by lower frequency induction and GPR; however, they are helpful for the design and installation for the perfor- mance and reliability of high-speed ICT wireline and wireless networks that support IPTV and video streaming. The TIA released Telecommunications Systems Bulletin TSB-162-A on Telecommunications Cabling Guidelines for Wireless Access Points 10 about the time of the 2013 release of IEEE 802.11ac 11 for very high throughput Wi-Fi, com- monly known as Wi-Fi 5. It basically recommends Cat 6A cabling to support WLANs, and it coincides with information from ANSI/BICSI 008-2018, Wireless Local Area Network Systems Design and Implementation Best Practices. 12 In January 2017, TIA issued TSB-5021, Guidelines for the Use of Installed Category 5e and Category 6 Cabling to Support 2.5GBASE-T and 5GBASE-T, 13 that includes "visual inspection procedures to predict the suitability and field test guidelines to determine the suitability of such cabling installations to support these applications, mitigation techniques to improve cabling performance, and recom- mends category 6A channels for new installations." In September 2018, ANSI/TIA-568-C.2 Revision D, Balanced Twisted-Pair Telecommunications Cabling and Components was published. 14 Similar to ANSI/TIA-1005, Telecommunications Infrastructure Standard for Industrial Premises, 15 these standards include two-mode conversion parameters that indicate balance: transverse conversion loss (TCL) and transverse conversion transfer loss (TCTL). TCL is mode conversion measured within a pair at the same end, and it is measured by injecting a differential- mode signal into a twisted pair and then measuring the common-mode signal returned on that same twisted pair. The smaller the common-mode signal returned, the better the balance. TCTL is mode conversion within a pair measured at the opposite end, and it is measured by injecting a differential-mode signal into a twisted pair and then measuring the common-mode signal at the other end of the link on that same twisted pair. Since the amount of common-mode signal is length dependent, equal- ization must be applied to take insertion loss into account. Therefore, the more meaningful measure- ment is equal level TCTL (ELTCTL). Similar to TCL, the smaller the common-mode signal at the far end, the better the balance. This sounds very similar to the earlier discussion of how the CSP industry has tradi- tionally determined the longitudinal balance of its twisted pairs! Lastly, another standard worth mentioning is BICSI G1-17, ICT Outside Plant Construction and Installation: General Practices 16 that provides valuable information on cable sheath bonding and grounding for LAN cables between buildings. As of 2017, more than 70 billion meters of Cat 5e and Cat 6 cable has been installed over the last 12 years.