WHAT IS COMPUTER COMMUNICATION

COMPUTER COMMUNICATION

What is the data communication

Communication refers to the electronic transmission of any type of electronic information encompasses telephone communication, the transmission of television signals, data communication of all forms, electronic mail, facsimile transmission, and so on.

Data communication is the movement of encoded information form one point to another by means of electrical or optical transmission systems, such systems often are called communication networks.

Component of communication

1)SOURCE/SENDER: originator of the message.the component from where the information is transferred.

2) MEDIUM: The path through which the message flows.

3)SINK:

The mechanism that accepts the message.

* Terminal, microcomputer or mainframe often alternate as both a source (sender)or sink(receiver).

* MEDIUM is usually the communication line leased form a"common carrier".

BENEFITS OF DATA COMMUNICATION NETWORKS

(1) COLLECT DATA FROM REMOTE POINTS ANd transmit that the data to a centre point, vice-verse.

(2) facilitate the more efficient use of the central computer.

(3) improve day to day control of business by providing faster information toon flow.

(4) provide massage switching services to allow terminals to talk to one another.

(5)offer better and timely interchange of data among users.

(6)bring the power of COMPUTER closer to the user

USES OF DATA COMMUNICATION

(1) source data entry and collection
(2)real-time interactive network.
(3)remote job entry (RJE) data collection
(4) information retrieval.
(5) conversational time sharing.
(6) Message switching, etc.

CHARACTER CODE IN DATA COMMUNICATION

*ASCII

(1) developed by American National Standard Code for Information Interchange.
(2) Usually, 7-bit code(128 characters) and one parity (for error checking on the individual character);8-bit version also existed (256 characters I.e., extended ASCII) For graphics and foreign languages applications.
(3)widely used in data communication and PROCESSING.

*EBCDIC

(1) Developed by IBM for data processing(1 start,8data,1parity,1 stop in async 11 bit,sync 9 bits).
(2) 8-bit code I.e.,256 characters possible.
(3) If parity is implemented, a ninth bit will be used

*Baudot Code/Binary Coded Decimal (BCD)

(1) 5 Bit code derived from telegraphy.
(2)used for Information telex network (called telex code,telegraph code),speed is 150 bits per second or less.
(3)User "shift" characters to increase character set to 58 lid character combinations.
(4) Different collating sequence for letters and numbers e.g.,1 is higher than 9,A is higher than z.