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EVOLUTION AND REVOLUTION OF COMMUNICATION




Land line:
     Here, microphone converts voice into electrical signals, amplified and is sent through wire.  At the other end, electrical variations are converted into sound by the speaker.  Today electrical signals are converted into laser signals and sent through glass fibers.  We know land line is the two way communication (send and receive).
  
Radio: 
Here, electrical signals are superimposed on high frequency radio waves.  Then the radio waves are radiated from tower.  High frequency waves has high energy and they can travel to long distance.  When you put a powerful light on the top of a tower, it will spread to long distance.  Similarly, high wattage radio waves (invisible light) spread to wide area. Wireless communication had begun.  Voice only is sent over the radio.  It is a one way communication, receiving only.  At the receiving end signals are extracted from radio waves and fed to the speaker.

 TV:  
     Here, audio and video is converted into electrical signal.  These signals are carried by radio waves or microwaves.  This high frequency waves can be sent from a tower to a short distance only because they are stopped by earth's curvature.  Hence they are mainly sent from satellites, received, amplified and distributed to TVs through cables.  It is also one way communication.  But video goes in air.

 Internet:
     Then, computers and telephones were married and international network was born.  Instant two way communication become possible.  Text, picture, voice, video, data; everything can be sent both the ways.  It brought the curtains down on postal mail, telegraph, telex, etc.  But the telephones were mainly designed for voice transmission.  So there were hiccups in the Internet initially.  After the advent of 3G and 4G technology, the Internet speed increased and has gone wireless also.  Today we are able to stream or download a movie fast and easily.  

 Cellphone:
    Cellphone is a pocket device.  It is something like a radio but facilitates two way communication.  Being a pocket device, it works on small power.  It cannot contact with satellite.  So towers has to be built every 5 km.  An area is divided into number of cells.  Each cell is covered by a tower.  Cellphone brought anywhere, anything, instant  and wireless communication.  Cell phone had become the most sold item on this planet.

 Smart phone:
     I need not elaborate on the uses of smart phone.  I can simply say 'the world is in our pocket'.  

      Working from home is already a reality as for as files are concerned. Next we are moving into an era called "Internet of things".   One can switch on or off a fan or a fridge, lock and open the house from any remote place through net.  In future, a station master will be able to monitor and control the train traffic using an app in his phone. 

      So the revolution is taking place before our eyes.  It is going to be exciting in future.  This article is instantly published.  We have moved from 'Handwritten magazine' to 'blogs' in our lifetime itself.  
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