Date Added: May 2012
In many applications a communication link between two devices becomes essential. This communication can be wired or wireless. If two devices are close to each other (like a microprocessor control unit and a Memory) then wired link is preferred. However in many applications two devices are reasonably far apart. In such applications, the data transmission can be achieved using InfraRed (IR) and Radio Frequency (RF). Line Of Sight (LOS) path is required between the transmitter and receiver in IR communication and hence is not used frequently. Instead, RF communication is used in wireless sensor network as it implements a wireless link in which the waves can penetrate a limited number of walls.