Ways of communication

Information technology 

 "The scientific method of storing, arranging informations for proper use and to communicate them to others is called the Information Technology (IT)".
 Information technology is changing speedily. It is not long NOR30 when the telephone was the only device of communication within the country or abroad. Now-a-days, in addition to telephone, machine, computer and internet etc. are the main sources of contact. These sources have brought in contact the whole world. These devices of informations are transmitted in the form of Dund, picture and computerised data. 

Telecommunication 

 "The method that is used to communicate informations to far off places instantly is called "Telecommunication."
 Telegraph Telegraph was the early form of telecommunication through which messages and informations were converted into electric pulses by a transmitter. The current of these pulses is received far away passing through wires where these signals commprising electric pulses are converted into audible signals. These telecommunication devices are much better. 

Telephone 

Working principle of a telephone is similar to telegraph but conversation can be processed by it. A microphone is fitted in the telephone handset. It changes vibrations produced by conversation into electric signals which are transmitted along a wire to the receiver at the other end of the line.
 Here an electromagnet and a vibrating diaphragm change the electric signals again into sound. Network of telephone provides a contact between two telephones. In modern network exchange, contacts are made through optical fibre system, microwave transmission or via satellites.

 Cellular or Mobile 

Phone Radio technology is applied in a mobile phone. It is a type of a radio having two way communication. A mobile phone carries a radio transmitter and a receiver inside it. It sends and receives the messages in the form of radio waves. 
Our sound waves are converted into radio waves and then reach a nearby station which is linked with the telephone network. The area of each station works as a cell. 
When a call reaches from one cell to the other, the radio signals emitted by telephone get connected with the next station by an automatic system. Mobile receiver again changes the radio signals into sound. 

Photo-phone or video phone 

 Another latest form of the telephone is the photo-phone or video-phone. Contrary to a common telephone, speakers can see the pictures of each other. It is the height of electronic communication that the distant speakers feel acquainted with the physical existence of each other. 

Telex Machine 

 Tele printer and exchange machine send the documents through telephone cables by electrical signals to the other telex machine where original print is received. But before converting the document into electrical signals, it has to be typed on telex machine.
 Now its use is abolished to some extent.

 Fax Machine

 Documents of considerable importance are sent from one place to the other through fax machine with telephone line. Fax machine first gets the reflection of the document like photostat machine, changes it into electronic signal and then transmits it via telephone line. The message when reaches the receiving fax machine, it reproduces the signals in an image print on a paper again. 

Radio 

Marconi, an Italian scientist succeeded in inventing a radio, about twenty years after the invention of a telephone. Radio is such a source of communication in which message is transmitted by electromagnetic waves. At the studio of radio station when a speaker uses microphone for conversation his voice changes into electrical signals. 
These signal waves are spread all around by a high antenna. When these waves strike the radio aerial, a weak alternating current of the same particular frequency is produced. Similarly waves of some other radio stations also produce currents of their own particular frequencies. 
Tunning circuit fitted in the radio selects the station waves of the choice and strengthens them. This signal reaches the amplifier and then the loudspeaker changes the electric signals again into sound. Thus we hear the sound broadcasted from a place hundreds of kilometre away.

 Television

 Picture and sound reach us via radio waves or a cable on a TV . At TV station moving pictures and sounds are converted into electric pulses, then their audio video signals are prepared and broadcasted all around by a high antenna, which scatter in all directions in the form of electromagnetic waves. 
When these waves strike the TV antenna, it produces very weak alternating current of the same frequency. Specific instruments fitted in the TV set separate the sound and picture signals, which are strengthened by the amplifier, TV tube displays the picture part of the audio video signal on TV screen whereas sound is received through the speakers.
 Instead of broadcasting, EM waves are sent to a TV set via special wire called 'Cable'. High quality picture and sound is received with the help of a cable. 

Computer

 

Monitor

 

 Computer is an electronic machine which after analysing and arranging the given information, presents it in a very short time. 
 All the work is done by the computer in the light of those instructions which are called a 'Programme' and is saved in its memory. Computer preserves this programme and informations in its memory so long as we desire. The important parts of a computer are given below: Input Devices In the computer, calculations and instructions are inserted by an input unit.
 Usually a key board, similar to a type writer is used for this purpose. The different functions of the keyboard are also controlled by a special instrument called a 'mouse'. There are several other methods to feed information into the computer which include floppy discs and CDs.
 Input devices send the received data to CPU so that its arrangement and analysis may be done. Central Processing Unit (CPU) It is a type of a brain of the computer which performs the whole job. This part comprises of a control unit and a memory unit ill. Output Devices 
The internal working of the computer is represented by the output unit. It resembles a television set which is called a monitor. All the processes can be observed on its screen while the print out of the result can be taken on a paper with the help of an attached printer. Moreover output can be recorded on a floppy disc or CDs. Fast working of the computer, accurate solution of the given information, large memory and capability of deriving results is increasing its importance day by day and perhaps there is no department left where man is not benifiting from its uses. 

Internet

 Internet is a system with which we can know the global conditions within no time.
 Not only the informations on internet about the whole world are available but it has revolutionized the communication techniques. This new invention has given a large projection to communication. E.Mail One can not imagine a speed greater than that by pressing a button you can send your message anywhere in the world. This source of communication is said to be an E-mail. Internet users are provided the facility to send their messages or graphics and the receiver checks them in his spare time. 

Websites 

 Another important feature of the internet are world websites which is a wide storage of information. Cable Internet is infact an interconnection of millions of computers/It is neither for one person, nor is the possession of one. It is beyond imagination that a person or a department individually may run the internet. Internet society is a group of many departments which controls the internet. Internet is actually a process using which people can contact each other through computer. This contact is usually made via telephone line or cable. All computers linked with internet use uniform communication process and same code. 

Internet protocol

In the internet terminology, it is called 'protocol' whose name is TCP / IP. It is an abbreviation of transmission control protocol / internet protocol. This protocol controls the transmission and transmits a small portion of the information at a time. 
This process is repeated millions of times per second. The language which is used in the internet web is understood well by all the computers linked with it and this language is called HTML which is an abbreviation of Hypertext Markup Language.
 Computers linked with the internet can exchange their information or can use the data base. In the beginning internet facility was limited to the government departments or big libraries, but the modern ways of communication have extended this facility. Now-a-days, not only national but at the international level, internet is an important and fastest medium of information. Students and teachers having contact with the internet can get information of any kind and about any subject. Businessmen can advertise their product by it. 
Doctors can exchange latest informations about medical problems. In short, information concerned with every department can be obtained from the internet. Remote Control System It is an extremely useful instrument. The function of a television and some other electronic machines can be controlled by it from a large distance without any cable connection.Infrared radiations are used to operate it. 
When any button placed at its panel is pressed, the bulb in control circuit generates a Particular binary code signal. This signal emits, from a light emitting diode called LED, an infra red radiation of the same Particular code. 
 When these radiations fall on a lens fitted in a television or any other electric machine, then a photo transistor attached with the lens identifies and sends them to a circuit which decodes the binary signal and issues the order accordingly. Thus we can control the function of the television or other appliances from a far off distance by a remote control system.

 Information Storing Devices 

The world's information in the form of encyclopedia has been printed on paper, but the information is increasing so rapidly that to get some information from it or to control its weight and volume has become very difficult. So the trend has increased to use such methods which do not use paper. So audio-video tapes, compact discs, laser discs, floppy discs and hard discs are in use for storing information. 
These devices can store a huge amount of informations in a very small space. We can benefit from anyone of the devices as we require. Usually storage devices work on the principle of magnetism whereas laser technology is used in CD's. 

Audio and Video Cassettes 

Audio cassettes consist of a tape of magnetic material , on which sound is saved in a particular form of a magnetic field. For this purpose microphone changes sound waves into electric pulses which are made by an amplifier. Magnetic tape of the cassette is moved through the head of audio cassette recorder which is in fact an electromagnet .
 Change of current in the wire wrapped on the electromagnet causes a change in the linked magnetic field. Thus magnetic tape is magnetized in a particular form according to rise and fall of current. In this way sound is stored in a specific magnetic pattern in this tape To produce the sound again the tape is moved past the play back head . 
Changes in the magnetic field on the tape induces alternating current signals in the coil wrapped on the head. These signals are amplified and sent to the loudspeakers which reproduce the recorded sound. In video tape . Pictures are recorded alongwith sound. 
 Compact Disc (CD) Compact disc is a digital disc. Instead of wavy grooves, a pit pattern is formed on it. This pattern comprises of billions of pits of varying lengths and spaces set on a shiny disc. Their arrangement depends upon the variation of sound. area between two pits is called a 'flat'. Pit pattern can be read by a laser beam . 
Laser beam is focussed on a track, it moves slowly across whole of the disc and the flats reflect the beam whereas pits do not. Thus after reflection when beam touches the head it indicates 1, hence the decoder receives a digital signal which changes it into a continuously varying electric current. It is then sent to an amplifier and the loudspeaker. Computer data is also stored in the CD's. While using CDROM (Read only Memory) in computer data is only read and it can not record. While reading the data, computer head does not touch the CD. 
That is why it is durable. Its storage capacity is many times greater than the floppy disc. About 650 MB (mega bite) data can be stored in it. It is packed in a box so that environmental pollution may not affect it. Movies can be stored in CD's which can be displayed on the computer or TV screen. Floppy Disc Floppy disc is made of flexible plastic which is coated with ferromagnetic compound. The disc is housed in a protective jacket having several holes cut in it which perform as given below: 
 Write Protect Notch If write protect notch is opened, data can not be entered on the disc and no alternation can be done in the previous data. If the slot is sealed then data can be entered on the disc and alterations can also be done in it. Central Hole Floppy get fixed on a rotating rod or the spindle and can revolve. Index Hole Near the central hole is located a small hole used to identify the starting position of the track. 
Read/Write Hole Disc drive head R/W using this hole can read and write the data. The data is stored on about 2 cm strip of the disc. Floppy disc can store a data of about 1.44 MB. Hard Disc Hard disc is installed inside the system unit. It is made of aluminum and hence it is not flexible.
 It is enameled with a layer of a material. (Fe, Co, Kr, Ni) that can be magnetized easily. Hard disc has higher speed and larger capacity as compared to other discs. This disc is also called the storage disc. Using this disc and by a control board a large number of informations can be read and written. Hard disc is made by joining many plates. 
This disc revolves in an enclosed box, with great speed about an axis To keep in a closed jacket is to avoid exterior pollution. Because of its large capacity it has high density of data compared to other discs. Word Processing Word processing is such a use of computer through which we can write letters, prepare reports and books. 
Word processing is a computer programme. By means of this we can develop any document, see it on the screen after typing. Edit it, add some new text or delete the previous text or do the amendments in it. Document can be stored in memory and its print can also be taken. By means of modern word processing, we can write it in different styles and in different colours. We can also use graphics. In computers this facility is also available which points out the spellings or grammatical mistakes. 
The content list and index etc. can also be made easily. To type something 'by computer's keyboard, to correct, to arrange, to amend the document, to add and delete the written portion when required is called'the word processing'. Graphic Designing The process to draw a required line or pictures on a computer screen using mouse or keyboard is called the graphic designing. Designs of the buildings or components can also be drawn with the help of computers. 
This process is named as computer aided designing (CAD). Three dimensional (3D) coloured pictures can be drawn by this process which can be checked by rotating it at different angles. Moreover different colours can also be selected for the pictures. This process because of accuracy and comfort is very popular in industrial field.

 Data Managing 

 To collect all informations regarding a subject for any purpose and to store them in the computer in more than one inter linked files which may help when needed, is called 'data managing'. The educational institutions, libraries, hospitals and industries store the concerned information by data management. 
Additions and deletions are made in the data according to the requirement, which help in the improvement of the management of the institutions. In -big departmental stores and super markets optical scanners are used to read, with the help of a Laser Beam, to read the Bar Codes of a product which indicates the number at which this product is recorded in the register.
 In this way the detail about its price is obtained and the central computer monitors the bills and the related record of the sold goods. It also helps placing the order for goods being sold in a large quantity and to decide about less selling goods.