use of electronic communication

use of electronic communication
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电子通讯的应用
电讯的应用
This section is devoted to the development and use of global communications between individual people and also between groups of people.
Since the invention of writing some thousands of years ago,people have been able to communicate with others across extremely long distances.There have been systems for delivery of written documents from single messengers carrying mail by foot,through couriers on horseback (the pony express was a prime example),to documents being carried on aircraft.Come what may,these systems of delivering the written word have their limitations.Post can get lost.It also takes time for it to be delivered (even an aircraft takes most of a day to travel half way round the world).
Humans have continually strived to speed up and improve methods of communications,in the same way that they have attempted to speed up travel times.The first major breakthrough in communications was the invention of the telegraph in the 19th century.This paved the way for instant communication over any distance round the world.
Having achieved the telegraph,the goal of voice communication over distance was an inevitable target.The telephone was born,and the system that has built up around it has made possible a lot of the modern communications methods.At present,the standard telephone differs little in its function from the original that Bell invented.The telephone system,however,has been put to many new uses in the past 30 years or so.In terms of communicating information,the voice telephone has one major problem - it creates no permanent written record.This means that documents have to be sent,as well as having a spoken conversation about them.