The Physical Layer is the lowest layer in the OSI (Open Systems Interconnection) Model of computer networking and is used to transfer electrical signals that represent data from one place to another. While the Physical Layer does not represent data itself, it does provide a means for that data to move. Essentially, the Physical Layer represents the hardware of a computer network and consists of everything from the circuit boards and wires to the storage devices and media readers.
How The Physical Layer Works
The Physical Layer consists of different types of metal, plastic, and glass that are assembled in a way that allows electricity, light, and other forms of energy to be transferred from one location to another. Although the Data Link Layer, Network Layer, and Transport Layer are responsible for encoding data, the Physical Layer is responsible for transferring the data to where it needs to go. When a computer has encoded data that needs to be sent to another device, it uses the Physical Layer to transfer electrical signals or wireless radio waves to that device by either induction (a signal jumps from one wire to another) or propagation (a signal expands in all directions).
The Physical Layer is one of the most commonly used layers in the OSI Model and can be seen by the user at all times. Every wire, circuit board, modem, router, flash drive, hard drive, monitor, or antenna that a user interacts with while using a computer is a part of the Physical Layer.