Issue link: https://www.e-digitaleditions.com/i/1347119
58 I ICT TODAY An MPTL configuration is now recognized within TIA and BICSI standards as an option for connecting devices wherever the use of an outlet and patch cord is not feasible. FIGURE 7: Contact geometry can impact performance of connectivity in PoE deployments due to arcing that occurs when unmating under PoE load. in the fully mated contact position. Figure 7 depicts the difference between a flat jack contact shape and a crowned jack contact shape. Note that with the crowned jack contact, any potential damage due to arcing occurs well away from the final contact mating position on both the jack and the plug. When selecting connectivity for PoE deploy- ments, one may also want to consider those that have been independently certified for compliance to the IEC-60512-99-0011 standard, which was specifically devel- oped to ensure reliable connections for remote powering applications deployed over balanced twisted-pair cabling. This standard specifies the maximum allowable resistance change that mated connections can exhibit after being subjected to 100 insertion and removal cycles under a load condition of 55 V dc and 600 mA applied to each of the eight separate plug/outlet connections. Plug contact Plug contact Plug contact Arc location during unmating under PoE load Arc location during unmating under PoE load Erosion and pitting on both jack and plug contacts Damaged plug contact in mated position can result in unreliable unstable connection Undamaged mated position provides a more reliable, stable connection Plug contact Flat jack contact Crowned jack contact Erosion and pitting on both jack and plug contacts