This is the second entry and i hope you readers are looking forward to read it as more and more new knowledge would be spread out through this particular site. As for this entry, we are moving on to the second lecture of this subject which was on the topic of DATA COMMUNICATION.
As we all know in the means of data communication, it involves mostly the use of computers, no matter where and how it is used. Computers are now made useful in every single ways and paths of life. Below we can see that computers are used in various places.
|The children in schools uses computer|
|Not to forget, even in universities ^^|
Let's move deeper into this topic and we will discover what it means by data communication. Basically, after the lecture, what I discovered was that data communication is defined as the collection and distribution of the electronic representation of information from and to remote facilities by means of electrical transmission system. For example, the electrical transmission can be through telephone lines, satellites and also coaxial cable. Have you guys ever heard of something called RAW DATA/INFORMATION? Well, when I saw this word, it somehow came to my mind that I've heard of it somewhere and at sometime in my life which I don't remember. For your information, this term actually means the information that could appear in a variety of formats. For instance, data, text, graphics, voice and still pictures and these formats must be digitized.
TYPES OF SIGNALS
From what I've learnt in the lecture, there are two types of signals that are needed to be converted from one to another which are Analogue Signal and Digital Signal.
|You see the difference between the two waves? ^^|
-An example: Human voice
-Analogue signal or wave is formed by continuously varying voltage levels that create a wave that can be grasped by an analogue transmitter like a microphone.
-Digital signal is a transmission of binary electrical or light pulses that only have two possible states which are 0 and 1.
-0 and 1 are the language of computers.
Note: The process of changing the analogue signal to a digital signal is known as MODULATION.
The process of changing digital signal to an analogue signal is called DEMODULATION.
Alright readers, let's move on to a small partial of this topic where it is regarding the binary digit or we also call it bit. Do you guys want to know something? This thing that you call bit are actually the basic or the smallest unit of measurement in a digital wave. Data capacity, does this term ring the bell? Here's a little info for you readers to have a quick glimpse at, the bit or also known as data capacity.
8 BIT = 1 BYTE
1000 BYTE = 1 KILOBYTE
1000 KILOBYTE = 1 MEGABYTE
1000 MEGABYTE = 1 GIGABYTE
1000 GIGABYTE = 1 TERABYTE
DATA TRANSMISSION MODE
Did it ever cross your mind on things about the transmission of data and how many ways it moves? I suppose not everybody is aware of this matter, so was I before I learnt this. Well, if you readers want to know, there are generally two patterns of data transmission that was taught by Dr Dayang, my lecturer. Firstly, it's parallel transmission where the group of bits as mentioned on top is transferred simultaneously by using a separate line for each and every bits. The second transmission mode is serial. In this case, the bits are transmitted one after the other on a single line and this is slower compared to the parallel transmission.
Moving on, synchronous and asynchronous are the ways of transmission for the serial pattern. I will only write on how the asynchronous transmission works as this is the one that mostly catches my interests. Unfortunately, I know that dragging the explanation would make this so dull so tadaaaaaa! I provide you readers with some pictures, so give it a sight okay! ^^
|Skype! It's one example that undergoes asynchronous transmission.|
|Not leaving out this- Video Conference. :)|
Simplex, half-duplex and full duplex, these are the three distinctive operations that takes place during a data flow which happens between two pieces of equipment.
Simplex: Data is transmitted in one direction only.
Half-duplex: The message can flow in two directions but never at the same time.
Full-duplex: Both station can transmit and receive the information simultaneously.
|Walkie Talkie- An example of half-duplex.|
|Radio experiences simplex operation|
Hope you readers have enjoyed reading and scrolling through this page as to add up to your buckets of knowledge. As for me, I am really looking forward to my next lecture and share with others the input that I have gained. Till then, happy reading folks! ^^