Wednesday, 7 March 2012

Week two- Data Communication

Today is week 2 of the class and today we learn about data communication. ^^

It is basically define as

  • collection and distribution of electronic information to and from remote facilities by means of electrical transmission system.   
Some of the communication devises include telephones lines,  satellites or  coaxial cable

Information need to be converted into signal understood by the media so that data can be transmitted. There are 2 types of signal : Analog vs Digital

Analog signal needs to be converted to digital signal of binary digit 0 and 1 as it is the language of computer. This process is called modulation while the reverse is called demodulation 

Binary digit is the smallest unit of measurement in digital and it consist of 0 and 1.

  • 8 bits = 1 byte
  • 1024 /1000 bytes = 1 kilobyte 
  • 1000 kilobytes = 1 megabyte
  • 1000 megabytes= 1 gigabyte

Parallel transmission is the transfer of data simultaneously while in series transmission, each bits is transfer after one another using the same line. For this reason, it is slower than parallel transmission.    

There are three types of data flow ; Simplex, Half - Duplex and Full Duplex


  • transmission in one direction only
  • no interaction between both receiver and transmitter as their role is fixed   
  • etc: TV, radio

Half- Duplex

  • Message can flow in 2 direction but never at the same time
  • One station transmit info to another without interruption and the other station will respond after the transmission is complete.
  • etc: Walkie- talkie

Full- Duplex

  • Both station can transmit and receive signal at the same time. It is the most interactive way of communication among the three.
  • etc: telephone line, tele- conference 

well, i guess this is all from me for time being. Below is a video for you all to enjoy. Thank you and peace to the world ^^.  

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