I wanted to know what made a Duplex system work? I always thought it was the Switch that made it work. But I just read on my Cisco course 2 things that made me question it. It said this, and made me believe it was the cable's properties that made Duplex work.
The frames sent by two connected devices cannot collide, since these use two independent circuits inside the network cable.
Full Duplex connections require a switch that supports Full Duplex configuration or a direct connection between two devices using an Ethernet cable