What is it?
The physical layer is the first and lowest layer of open systems interconnection (OSI), i.e., a reference model for how applications communicate over a network. This model illustrates a consequential arrangement for communications layers, from cabling to applications that interact with the network’s devices.
The goal of the physical layer is to transfer data with the help of electrical, mechanical, or procedural interfaces.
How does it work?
The layer in question is closest to the physical link between devices. It encompasses items like cabling, connectors, receivers, transceivers, and repeaters. Additionally, the physical layer serves as the basis for other layers.
Functions of the physical layer
First, the physical layer is responsible for defining bits, namely determining the way bits are converted from zeros and ones to a signal. The second is deciding on the data rate (how fast data flows in bits per second).
The physical layer is also intended to ensure that sending and receiving devices are synchronized. Next, it determines the direction of data transmissions and decides whether these are going to be simplex (one signal goes in one direction), half-duplex (data is transferred in both directions but not at once), or full duplex (data is transported in both directions at the same time).
Defining the way devices are linked to the transmission medium (interface) is one more purpose of the physical layer. Even more, it ensures point-to-point and multipoint configurations, transforms data into radio waves (modulation), sends data packets from port to port (switching), and performs signal equalization.