1. Physical Layer


In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first (lowest) layer. The implementation of this layer is often termed PHY.



Within the semantics of the OSI network architecture, the physical layer translates logical communications requests from the data link layer into hardware-specific operations to effect transmission or reception of electronic signals.


  1. http://en.wikipedia.org/wiki/Physical_layer