Introducing Introducing Data Communication & Data Communication &

TelecommunicationTelecommunication

Data Communication versus Data Communication versus TelecommunicationTelecommunication

• Data communication is the transmission of data from one place to another (usually computer to computer) over some type of medium such as telephone line. It refers specifically to the communication network which limited in the type of data transmitted

• Telecommunication may includes communication system that are not considered as data communication systems. E.g. Telephone

Data Communication versus Data Communication versus TelecommunicationTelecommunication

Trans

miss

ion

and

rece

ipt o

f

Transmission

and receipt of

Analog data

e.g. voice, video, radio, tv

Digital data

(Data processed by computers)

Telecommunication

Da ta

Co m

mu n ic at io n

Standard OrganizationStandard Organization

IEEE – Institute of Electrical and Electronics Engineers. Professional organization whose activities include the development of communications and network standards.

ANSI – American National Standards Institute. Voluntary organization composed of corporate, government, and other members that coordinates standards-related activities, approves

U.S. national standards, and develops positions for the United States in international standards organizations.

Standard OrganizationStandard Organization

ISO – International Organization for Standardization. International organization that is responsible for a wide range of standards, including those relevant to networking. ISO developed the OSI reference model, a popular networking reference model.

EIA– Electronic Industries Association. Group that specifies electrical transmission standards. The EIA and TIA have developed numerous well-known communications standards, including EIA/TIA-232 and EIA/TIA-449.

Standard OrganizationStandard Organization

TIA – Telecommunications Industry Association. Organization that develops standards relating to telecommunications technologies. Together, the TIA and the EIA have formalized standards, such as EIA/TIA-232, for the electrical characteristics of data transmission.

Basic Components of a Basic Components of a Communication NetworkCommunication Network

A data communication network is composed of three parts:-

SOURCE – It is a device used to send the message (e.g. personal computer, telephone or any other device that can be connected to a network)

MEDIUM – It is a physical path that connects the source and the receiver and is used to transmit the data (e.g. STP, UTP, coaxial, fiber optic)

RECEIVER – It is a device that accepts the message and may not be similar to sender

Basic Components of a Communication NetworkBasic Components of a Communication Network

Modes of Channel / Data Flow: Modes of Channel / Data Flow: Simplex, Half- and Simplex, Half- and Full-Duplex CommunicationsFull-Duplex Communications

• Simplex - Connection that allows communication in one direction

• Half-duplex– Connection that allows communication in two

directions, but not simultaneously• Full-duplex

– Connection that allows communication in two directions at once

Half- and Full-Duplex CommunicationsHalf- and Full-Duplex Communications

• Benefits of using full duplex:

– Time is not wasted retransmitting frames because there are no collisions

– Full bandwidth is available in both directions because the send and receive functions are separate

– Stations do not have to wait to until other stations complete their transmission because there is only one transmitter for each twisted pair

Transmission Modes: Transmission Modes: Serial and ParallelSerial and Parallel

Data may be transmitted between two points in two different ways. It can be transmitted as entire characters or as individual bits.

In computers, these bits may be sent all at once (in parallel), or one after the other (serial).

Transmission Modes: Transmission Modes: Serial and Parallel Serial and Parallel

In parallel transmission the entire character is transmitted all at once

Each bit uses a separate wire. Thus, 8 bits character require 8 wires.

For serial transmission, each bit is sent over a single wire, one after the after.