You do not need a 2 pair (4 wires) Ethernet cable when connecting your PC to a normal HUB. This is because normal hubs do not carry power sync. The question about using straight or cross-over cables depends on the network design. Most normal hubs are not auto sensing like the Furuno HUB-101. The Furuno hub auto senses the cable and if you used a straight cable but should have used a cross-over; it will still work. Most normal hubs won’t work unless you use the correct type of cable. When networking, normally you use straight cables into the hub and allow the hub to conduct the “cross” to make everything talk. A cross over cable is normally used when doing a direct connection between two network devices without a hub. Unlike normal hubs, The Furuno hub is designed for boat power, offers NN3D power sync, and has auto sensing ports. In some NN3D installations a normal hub works fine, but you must be more careful on the cables and system design.