Functions of the OSI Layers - Physical Layer

Functions of the OSI Layers

Functions of different layers of the OSI model are presented in this section.
1.2.4.1 Physical Layer
The physical layer is concerned with transmission of raw bits over a communication channel. It specifies the mechanical, electrical and procedural network interface specifications and the physical transmission of bit streams over a transmission medium connecting two pieces of communication equipment. In simple terns, the physical layer decides the following:
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Number of pins and functions of each pin of the network connector (Mechanical)
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Signal Level, Data rate (Electrical)
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Whether simultaneous transmission in both directions
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Establishing and breaking of connection
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Deals with physical transmission
There exist a variety of physical layer protocols such as RS-232C, Rs-449 standards developed by Electronics Industries Association (EIA).