I don't recall seeing a board-mounted Ethernet jack that didn't have metal sides. Reasons for an Ethernet jack to include a small metal enclosure: 1. The jack

I don't recall seeing a board-mounted Ethernet jack that didn't have metal sides. Reasons for an Ethernet jack to include a small metal enclosure: 1. The jack is subject to physical strain as we insert, remove, and tug on the cables. Most components are affixed to the board using only solder on the signal leads, but these do not provide significant mechanical strength. If you've ever had a bad headphone jack on personal electronics you are familiar with this phenomenon. So the little metal box has additional metal tabs that fit snugly in holes or slots on the board, and provide a stronger mechanical fit and a much larger surface area for solder adhesion. 2. Electromagnetic interference compliance. While Ethernet by definition involves pumping gigahertz signals out a long wire, these signals are carefully shaped and the cables pairs twisted to reduce leakage. But the designer of the jack doesn't know how much EM is flying around inside the case into which the port will be fitted. A metal box around the jack minimizes the size of the unshielded opening in the case. If you've installed a PC motherboard, you know the springy metal fingers on the backplate that seal against the block of external ports. Is it possible the article is talking about an Ethernet cable plug? I have occasionally seen those with metal sides. But they are not normally supplied as part of a motherboard or server.