An Ethernet crossover cable is a crossover cable for Ethernet used to connect computing devices together directly. two computers (via their network interface controllers) or two switches to each other. This guide gives you clean wiring tables, quick “when to use” rules, modern notes on Auto-MDI/MDI-X, and deployment. Crossover Ethernet cables are a key solution for direct, reliable device-to-device communication in modern networking. They are used to send and receive data by enabling complex data transfers between computers, routers, and networks.