What Is Data Communication? – The term communication means sending or recieving information. When we communicate, we share information or data.
A Communication system can be defined as the collection of hardware and software that facilitates intersystem exchange of information between different devices.
What Is Data Communication?
It is the exchange of data between two devices using some form of tranmission media. It includes the transfer of data or information and the method of preservation of data during the transfer process. Data is transfered from one place to another in the form of signals.
There Are Three Types of Signals:-
- Digital Signal :- In This signal, data is transmitted in electronic form of data. i.e binary digits (0 and 1).
- Analog Signal :- In this signal, data is transmitted in the form of radiowaves like in telephone line.
- Hybrid Signal :- In this signal, have properties of both analog and digital signal.
The Communication Channel refers to the direction of signal flow between two linked devices.
Types Of Communication Channel
There Are Mainly Three Types of Communication Channel:
- Simplex Channel :- In This channel, the flow of data is always in one direction, with no capability to support response in other direction. This communication is unidirectional. Only one of the communicating devices transmits information and other can only receive it. eg. Radio, Television, Keyboard.
- Half Duplex Channel :- In This channel, the data can flow in both directions, but not at a same time. When one device transmits information, then other can only receive at that point of time. eg. Walkie-Talkie.
- Full Duplex Channel :- In This Channel, the flow of data is in both directions at a time. i.e both stations can transmit and receive information simultaneously. e.g Wireless Handset (mobile phone).
Communication Media of a network refer to the transmissin media or the connecting media used in the network. It can be broadly defined as anything that can carry informatin from a souce to destination. It refers to the physical media through which communication signals can be transmitted from one point to another.
Transmission/Communication Media can be divided into two broad categories:-
Guided Media or Wired Technologies
The Data signal in guided media is bound by the cabling system that guides the data signal along a specific path. It Consists of a cable composed of metals like Copper, Tin or Silver.
- Ethernet Cable Or Twisted Pair : – In This pair, wires are twisted together, which are surrounded by insulating material and an outer layer called jacket. A twisted pair consists of two conductors (Copper). One of the receiver and the other used as a short distance communication. eg. Local Area Network use Twisted-Pair Cable.
- Co-axial Cable: – It Carries the signal of higher frequency data communication through the network. It Consists of a solid wire core surrounded by foil shielded or conducting braid or wire mesh, each separated by some insulator. it has a single inner coductor that transmits electric signals and the outer conductor acts as a ground and is wrapped in a sheath of teflon or PVC. Co-axial cable is commonly used in trasporting multi-channel television signals in cities. e.g Cable TV Network.
- Fibre Optic Cable :- It is made up of glass or plastic and transmits signals in the form of light from a source at one end to another. At the source, there are either Light Emitting Diodes (LED) or Laser Diodes (LDs), which modulate the data into light beam using frequency modulation techniques. Optical fibres allow transmission over longer distance at higher bandwidth which is not affected by electromagnetic field. the speed of opticle fibre is hundread of times faster than co-axial cables.
Unguided Media Or Wireless Technologies
It is the transfer of information over a distance without the use of enhanced electrical conductors or wires. when the computers in a network are interconnected and data is transmitted through waves, then they are said to be connected through unguided media.
Some Commonly used Unguided Media of transmission are:-
- Radiowave Transmission:- When two terminals communicate by using radio frequencies then such type of communication is known as radiowave transmission. This transmission is also known as Radio Frequency (RF) Transmission. These are omnidirectional. Radiowaves, particularaly those waves that propagate in the sky mode, can travel long distances. Each computer attaches to an antenna that can both send and receive radio transmission.
- Microwave-Transmission:- Microwaves are electromagnetic waves having frequencies range from 0.3 to 300 GHz. Microwaves are unidirectional. Microwaves have a higher frequency that that of the fastest media for data transmission over communication channel. They can be aimed at as single direction, instead of broadcasting in all direction. Microwave antenna placed on the top of buildings. It consists series of stations approx 30 miles apart. It is used in Cellular network and television broadcasting.
- Infrared Wave Transmission:- Infrared waves are the high frequency waves used for short-range communication. These waves do not pass through the solid-objects. They are mainely used in TV remote, wireless speaker.
- Satellite Communication:- The communication across longer distances can be provided by combining radio frequency transmission with satellite. it works over a long distance and fast communication amplifies signal received from one earth stations and again retransmits to another earth station, which can be located many thousands of miles away. it is used for communication to ships, vehicles, planes and handheld terminals.
Bluetooth – Bluetooth is wireless technology used for exchanging data over short distances to create a Personal Area Network (PAN).
Bandwidth – Bandwidth determines the data transfer rate which is measured in Cycle Per Second (CPS) or Hertz (Hz)
Throughout – Troughout is the amount of data that is actually transmitted between the two computers. it is specified in bits per second (bps) Giga Bits Per Second (Gbps) is the fastest speed unit per data transmission.
Band – Band is used to measure the speed of signaling and data transfer.
If You Read This Blog Please Share To Your Friend And Family.
For More Hacking Blog Click Here