History of Communication Development

 

1. Ancient times people communicate by talking face to face communication, by the sound, the sound is a sound wave, a mechanical waves, need water or air as a medium to deliver a substantially sonic energy propagation, the attenuation speed, propagation relatively short distance.
2. But when people need long-distance exchange it? Sound propagation past, so people through the flames, smoke signals, semaphore exchange, which is actually to transmit information by light, light of a specific wavelength of the electromagnetic wave oh. But this transmission limited distance.
3. The era of long-distance communications as well as IP Messenger, marathon and other information media to humans and animals to spread. For example, post, pigeons, dogs letter, carrying text-based, slow and costly. (Text appears in 6000 before)
4. With the discovery of electricity, electricity has been found possible to disseminate information as the medium, then the invention of the telegraph. Telegraphic messages transmitted via a dedicated line so as to exchange an electric signal out of the signal and the digital coding instead of words, coding is generally used Morse code (1837)
5. Appeared phone, the phone is a human sound wave into electrical current, to pass through to the other end of the current, then the current is converted into sound waves, but the phone needs a telephone line, a mobile object communication is not possible. (1860)
6. Because the electrical transmission wires needed, they can not do wireless communication. With the discovery of electromagnetic waves, the emergence of mobile phones, the phone will convert sound into electrical signals, and then the electric signal is sent using a mobile phone antenna in the form of electromagnetic waves. This time the phone is on behalf of Big Brother, it is 1G era of mobile communications, and can transmit voice (1940 invention)
7. The basic principle is that the communication computer converts the electrical signal into a logic signal which is the high-low mode conversion is expressed in binary numbers 0 and 1, and then all of the information represented by different binary sequences. (1950s and 1960s)
8. Second generation communication technology (2G) digital communications technology, 1G analog communication techniques. Digital communication techniques that voice, text by encoding becomes 0 and 1, and then out of the receiving end according to 0 and decoding. So 2g can send text messages. (year 1991)