An Ethernet crossover cable is a type of Ethernet cable used to connect computing devices together directly where they would normally be connected via a network switch, hub or router, such as directly connecting two personal computers via their network adapters. Typical uses are: router to router, switch to switch, pc to pc, router to pc (Note: router and pc are LIKE devices, because both are DTE. Caution: home routers already have built-in adapter,so you can use straight through cable directly)