Router computing - Wikipedia.
A typical home or small office DSL router showing the telephone socket left, white to connect it to the internet using ADSL, and Ethernet jacks right, yellow to connect it to home computers and printers. A router may have interfaces for different types of physical layer connections, such as copper cables, fiber optic, or wireless transmission. It can also support different network layer transmission standards. Each network interface is used to enable data packets to be forwarded from one transmission system to another. Routers may also be used to connect two or more logical groups of computer devices known as subnets, each with a different network prefix.