Data link layer

The physical layer is the first and lowest layer of the OSI model and is responsible for transmitting individual bits between network devices. It defines the physical, electrical and technical characteristics required for data transmission, including signal levels, transmission rates, frequencies, connectors and cable types. Transmission media can include copper cables, fibre optic connections and wireless communication. Network devices such as repeaters and hubs primarily operate at this layer. The physical layer does not interpret the content of transmitted data but provides the fundamental connection required to transport it. It therefore forms the technical foundation for communication across wired and wireless networks.