06/08/2026
OSI Layer 1: Physical Layer
The Physical Layer is responsible for transmitting raw bits (1s and 0s) across a physical connection. It defines the electrical, optical, and mechanical standards used for communication, including cables, connectors, wireless signals, voltages, and data transmission rates. Devices that operate at Layer 1 include hubs, repeaters, cables, and network interfaces.
Examples: Ethernet cables, fiber optic cables, wireless radio signals, hubs, and repeaters.