Page 74 - Computer - 9(A&B)

Modem

A modem is a hardware device that connects a computer to a
communication line such as an Internet cable. Modem stands for
MOdulator-DEModulator. Modem can be of two types: external
modem and internal modem. An external modem is attached externally
External Modem Internal Modem with the computer, while an internal modem is connected to the
motherboard of the system inside the CPU box.

External Peripheral Devices
The components which are visible from outside and help the user to work on computer system are called external
peripheral devices. These components can be further categorized as input, output and storage devices.

Bar Code Reader
This input device is a kind of optical scanner consisting of a light
source, a lens and a photoconductor. It reads the data code available
on various products in the form of dark lines called bar codes. It
emits a beam of laser light to refl ect back the bar pattern which
is received by light sensitive detector in the bar code reader. The
received pattern is then converted into a numeric code which is Bar Code Bar Code Reader
further processed by the CPU.

Rahul has bought a product from the supermarket. At the billing counter, he saw an input device
that reads the barcode of the product. Which device was used by the counter person?

Memory Card Reader
It is a device that can read and write to a memory card or a memory stick. It is often
used to transfer data to computers or other devices for storage. Often, a memory
card or a memory stick displays as a ‘mounted drive’ on a computer. The main
functions of a card reader are:
 To quickly transfer fi les to an SD card or a compact fl ash drive.
 To take a backup of the most important fi les on the computer.
Some card readers only have one card slot, while some have multiple card slots for different cards and media.
The card readers may be integrated into a computer printer, and other multifunction devices. In fact, most
multifunction printers, scanners, and copiers now have built-in card readers.

Name the following.
a. An electronic circuit where all parts of the computer are connected._______________
b. An electronic circuit box that provides regulated power supply to the various parts of the computer.______________
c. An electronic card that provides input and output of audio signals from a computer.______________

Session 4
Perform Basic Computer Operations

Computer hardware and software are interdependent on each other. If any of these is not functioning properly,
a computer is of no use. In this session, you will learn the process to start a computer and know about software
and its types. This session also gives an overview of the commonly used operating systems.

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