Introductions of network and the computer communications

Generally the communication means the exchanging or sharing of message & ideas between the two or more people.So, there is two ways to send the messages to the people or for the friends.They are simplex and Duplex.

• The simplex is one way communication systems for e.g. sending the letters by the mail, email, fax, telex books or newspapers, radio etc.
• The duplex is the two way communication systems, for e.g. internet, videos conferencing, telephone, tele medicine, money transfer, tele teaching, e-commerce etc.

The computers that are made today is use for sending and receiving the informations as the telephone systems.So because of the computer it has been easy & possible to make the comunications between two person or organization.So, for this purpose, the computers in different distance are to be connected together by the some means of forming which is called a network.The computer network is group of computer which are link together for the purpose of communicating & sharing resources.

Suppose think that there are twenty schools in your locality or districts in different cities and are distance apart & all of the schools have theirs own computer.Suppose if any special events is occured in any of one school & that school want to invite the principal other school.Here a very fast communications is required.For the fast exchange of message between the schools the perfect communications is essential.So what can be done is the computers of different schools must be connected so that each of it can be worked on it's own & if need arises.Therefore the communication link.This link may be done by the copper wire, micro-wav channel or even by the satellite or any other medium.

Computer network is defined as the collections of indepedent computer connected through communication medium.For making network each and every computer must be able to work independently.There was remarkable and the great changes in the world of communication after 1994A.D.By using the computer network and the telecommunication, people can use computer for reaching, processing the records in other PC, retriveing and reinting the results on their own counters.So by the help of computer network and the telecommunications, followings services are being provided by the people to their customers.

1. Communication of Data

• Telegram
• Telex
• E-mail
• E-commerce, E-trade, E-mail, E-business

2. Communication of Voice(Transfer voice)

• Telephonic
• Radio

3. Communication of Videos(Transfering motion pictures)

• Video phone
• Television
• Video text
• Video conference

The above technology are being used by th people in today's world more than 20millions for their own purpose.They are busy in theri jobs throughout the days & night.For converting the characters, numbers, videos, texts in the electrical pulse & vice versa, all of them requires a device called MODEM which is the combinations of pair like Demodular & Modular.So to use the above technology mentioned, users need a computer, telephone set and modem.