DATA COMMUNICATION AND NETWORKING
Data Communication is a system consisting of carries and related devices used to transport datafrom one point to another. Communication means to convey a message, an idea, a picture or speechthat is received and understood clearly and correctly by the person for whom it is conveyed. Ancient Methods of Communication and Their Demerits
– Message were sent in olden timeseither through horse riders or by using pigeons. There was no surety that the messenger will be able toconvey the message exactly in the same form as told to him verbally. Electronic Methods of Communication –
With the invention of telephone instrument and thecommunication satellites, the means of electronic communication has become very popular in Indiaeven though the cost of installation and maintenance of telephones is still very high and beyond themeans of a common man. Limitations of Telephonic Communication
:(a)Both the sender and the receiver of the message should be available at the same time andshould speak the same language to understand.(b)Telephone communication is not a secured means of communication because anyone canoverhear the message.(c)It is not suitable to send picture or any other type of message except a spoken message.(d)It is affected by the electrical interference or by the people digging roads etc.(e)It is still quite costly to make a telephone call outside the city or the country. Computerized Communication
– Since the time computers have started playing an important role inthe field of communications. The main reason for this is that computers can send data extremely fast. They can even transmit pictures and sound in a much secured manner. Further, PCs can sendinformation on the existing telephone line. Advantage of Computerized Communication
–(a)Telephonic calls, using Internet, can be made to any part of the world with the same expensesas a local telephone call made within the city.(b)Pictures, sound...