Not anymore for all practical purposes, but it once did for the very old 10Base-2 standard for Ethernet over coaxial cable. This is practically why the old MII

Not anymore for all practical purposes, but it once did for the very old 10Base-2 standard for Ethernet over coaxial cable. This is practically why the old MII Ethernet PHY interface protocol had the collision-sense lines to indicate to the MAC to stop sending data if it detects incoming data, in attempts to minimize collisions. https://en.wikipedia.org/wiki/10BASE2 https://en.wikipedia.org/wiki/10BASE2