Physical Layer (OSI)

Physical Layer (OSI)

The physical layer is the first layer of the OSI model.

This layer is concerned with how network devices are physically connected. This includes the type of medium, such as copper, glass, and air. 

The physical layer is where data is converted into a stream of bits. These bits have to be encoded into physical signals in some way. That is, which signal represents a 1, and which represents a 0?

These signals may use electrical, light, or radio waves.