THIS IS A INPUT

DEVICE

TOUCH SCREEN

A touch screen is a monitor screen that allows users to interact

with a computer system by touching an area of the display

screen. The screen is covered with a clear plastic layer that has

a matrix of cells. A user touches a graphic button that displays

option on the screen. Touch screens are easy to use. Thus,

many kiosks use touch screens as input forms.

LIGHT PEN

A light pen is a light-sensitive pen-like device used by pointing it

at the display surface. A user brings the light pen to the desired

point on the screen and presses a button, causing it to identify

the current location. It is used to select options from a menu or

to draw images.

BAR-CODE READERS

A bar code is a specialized code represented by sets of parallel

bars of varying thickness and separation. This is used for fast

identification of items with an optimal scanner. The optical

scanner is called a bar code reader. The bar code reader is a

photoelectric scanner that read the bar code.

SCANNER

A scanner is a device that reads spatial pattern such as images,

graphics and texts, and then generates digital signals of that

pattern. Converted digital data may be processed by a

computer, stored in a disk, printed by a printer or displayed on a

monitor. Scanners are commonly used to capture graphic

images that can then be placed in a page or on any

document.Scanners usually include optical character

recognition (OCR) software so that scanners can read and

capture texts directly through optical scanning.

DIGITIZER TABLET

A digitizer tablet is also called a graphics tablet or just a

digitizer. The digitizer is a drawing tablet used to sketch new

images or trace old drawing or photograph. The user uses a

pen-like device called a cursor to draw images. Designers and

architects usually use digitizers. Light pen and digitizer

technologies are used for pen-based computing.

MAGNETIC ENTRY

There are two technologies in magnetic data entry. A magnetic

ink character recognition (MICR) technology reads iron oxide ink

preprinted or encoded on checks, deposit slips or on

documents. An MICR reader electronically captures data, by

first magnetizing the magnetic ink characters and then sensing

the signal.

Another form of magnetic data entry is the magnetic stripe

technology that makes computers read credit cards. The dark

magnetic stripe on the back of credit cards is the iron oxide

coating. A magnetic stripe reader reads this magnetic stripe.

VOICE-INPUT DEVICES

Voice input devices are also called speech- recognition devices

or voice-recognition systems. This device uses a voice

recognition technology that converts a user's speech into a

digital code. Spoken words are first digitized and then matched

against a dictionary of patterns previously stored in the

computer.

Speaker-dependent systems should be trained by taking actual

user's word sample before using, but speaker-independent

systems can recognize only limited vocabularies. The

advantage of the voice input systems is that they enable users

to keep their hands free for other tasks.

MOUSE

An object used as a pointing and drawing device. The mouse

usually has a ball and buttons and is connected to the system unit

through serial port. As a mouse is rolled across the flat desktop in

any direction, it locates the pointer correspondingly on the screen.

Then it issues commands using the selection buttons on the

mouse. Many portable microcomputers such as lap-tops use track

balls instead of mice.

THIS IS A OUTPUT

DEVICE

MONITOR

A computer display is also called a display screen or video

display terminal (VDT). A monitor is a screen used to display the

output. Images are represented on monitors by individual dots

called pixels. A pixel is the smallest unit on the screen that can

be turned on and off or made different shades. The density of

the dots determines the clarity of the images, the resolution

MODEM

Another form of the output device is a modem. A modem is short

for "MOdulator-DEModulator." Modulation is the process of

converting from digital to analog. Demodulation is the process

of converting from analog to digital.

The modem enables digital microcomputers to send output

through analog telephone lines. Both voice and data can be

carried over through the modem. The modem is not only an

output device but also an input device that receives data and

voice through a communication channel.

VOICE-OUTPUT DEVICES

This device produces a human speech like sound, but actually

is prerecorded vocalized sounds. Voice output is used in the

telephone information system, where the requested number is

reported using a voice output system.

For example, when a student enrolls courses using a telephone

registration system, he or she hears voice output upon your

request. Voice output is becoming common in voice messaging

systems

PLOTTERS

A plotter is a special-purpose output device that draws images

with ink pens. That is, the plotter is a graphics printer for making

sophisticated graphs, charts, maps, and three-dimensional

graphics as well as high-quality colored documents. It can also

produce larger size of documents.

Plotters require data in a vector graphics format that can

produce images with a series of lines. There are two main types

of plotters:

PRINTERS

A printer is an output device that produces a hard copy of data.

The resolution of printer output is expressed as DPI. Printers

can be classified into different types in several ways. First, the

printers can be divided into three categories by the way they

print.