If the links are operating at only 10Mbps or 100Mbps, it's possible for them to operate in half-duplex mode (e.g., if the cables don't have all 8 pins wired properly), even with a switch. In this mode, there's a collision domain between the host device and the switch.
huh? where "segment" means where you are using a hub not a switch? cuz that was a long time ago