Input / Output Devices

Keyboard layouts:

QWERTY arrangement

Dvorak arrangement

Keyboard keys classification Modifier keys:

Ctrl, Alt, Shift Cursor movement keys:

Home, End, Arrows, Page up, Page down

Types of Keyboards: QWERTY keyboard Enhanced keyboard

Wireless/ cordless keyboard

Types of Keyboards:

Portable keyboard

Ergonomic keyboard

Types of Mouse: Mechanical mouse

Optical mouse

Wireless mouseTransmitter & receiver

TOUCH PAD / TRACKPAD: It is used to position or move the curser

according to the finger movement on the touchpad. 

A touchpad is a pointing device featuring a tactile sensor, a specialized surface that can translate the motion and position of a user's fingers to a relative position on screen.

POINTING STICK: A small rubberized device located in the

center of a computer keyboard, which is moved with a finger tip to position a pointer. 

PEN INPUT: The mobile users usually input data and

instructions using a device like a pen for writing or drawing on a flat surface

Stylus: Stylus is a pointing and drawing device shaped

like a pen, and used with a digitizing tablet or touch screen. The stylus point is made of a  non scratching plastic  to "write" on Personal Digital Assistants (PDAs) or any similar device Screen. The input is given with pressure instead of ink

USING PEN INPUT: The pen input is used with touch screens A graphic tablet can be attached with the

computer if touch screen is not available. A graphics tablet (or digitizer, digitizing

tablet, graphics pad, drawing tablet) is a computer input device that enables a user to hand-draw images and graphics, similar to the way a person draws images with a pencil and paper.

These tablets may also be used to capture data or handwritten signatures. It can also be used to trace an image from a piece of paper which is taped or otherwise secured to the surface. Capturing data in this way, either by tracing or entering the corners of linear poly-lines or shapes is called digitizing.

GAME PAD: A gamepad (also

called joypad or control pad), is a type of game controller held in two hands, where the digits (especially thumbs) are used to provide input. Gamepads generally feature a set of action buttons handled with the right thumb and a direction controller handled with the left

GAME WHEEL: Output device that uses a steering

wheel and a separate set of foot pedals to imitate real world driving

AUDIO INPUT DEVICES: Process of entering any sound into computer is

called audio input Audio devices converts sound into a form that can

be processed by a computer Sound card is required to enter high quality sound

into PCMicrophone:  is an acoustic-to-electric

converter or sensor that converts sound into an electrical signal.

MIDI devices: are used to enter music and other sound effects from piano to computer

VOICE INPUT: The process of entering data by speaking into

microphone attached to computer Voice recognition/Speech recognition:

Ability of a computer to distinguish spoken words

Speaker dependent Software: Computer stores the voice patterns of words repeatedly spoken by user

Speaker Independent Software: User doesn't train the computer. Software has built in set of word patterns

IMAGE CAPTURING DEVICES:

Digital camera (or digicam): takes video or still photographs, or both, digitally by recording images via an electronic image sensor

doesn't require a roll of film Unwanted pictures can be erased preview your photos Quality of digital camera depends upon its

resolution Resolution: Image Sharpness

TYPES OF DIGITAL CAMERA:

Studio camera: a high-end device for creating electronic moving images 

Field camera:  a view camera that can be folded in a compact size. It has many lenses

Point and Shoot camera:   A still camera designed primarily for simple

operation. Most use autofocus for focusing, automatic systems for setting the exposure options, and have flash units

built in.

VIDEO INPUT Process of entering full motion recording into

computer Video capture card: An expansion card that

converts the analog video signal into digital signal.

Types of expansion cards:

Frame grabber video card: It captures and converts single frame at a time

Full motion video card/ Adapters: Converts 30 frames per second. It gives the effect of a motion picture

WEB CAMS/ PC VIDEO CAMERA

Stores its images in real time to

a computer or computer network, often

via USB, Ethernet, or Wi-Fi.

Webcams are known for their

low manufacturing cost and flexibility, making

them the lowest cost form of video

telephony. 

VIDEO COMPRESSION Compression decreases the file size,

allowing for a reasonable amount of download time or streaming capability but also decreases the quality of the video

A video codec is a device or software that enables video compression and/or decompression for digital video

Video Decoder decompresses video data Video digitizers captures individual

frame from an analog video and saves still picture in file.

VIDEO CONFERENCING: Conducting a conference between two or

more participants at different sites by using computer networks to transmit audio and video data

Videoconferencing is the conduct of a videoconference (also known as a video conference or videoteleconference) by a set of telecommunication technologies which allow two or more locations to interact via two-way video and audio transmissions simultaneously. It has also been called 'visual collaboration' and is a type of groupware.

OPTICAL SCANNER / SCANNER:

Captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. 

A device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. 

Typical scanners support resolutions of from 300 to 600 dpi. Professional scanner scans at 1200 dpi or higher.

Optical Character Recognition software reads the document image and converts it into the text that can be edited in word processor.

SCANNER & ITS TYPES

TYPES OF SCANNERS:  Flatbed scanner/ Image scanners, is like a

photocopy machine. It consists of a board on which you lay books, magazines, and other documents that you want to scan.

Sheet-fed scanners: Similar to flatbed scanners except the document is moved and the scan head is immobile. A sheet-fed scanner looks a lot like a small portable printer. Handheld scanners: use the same basic

technology as a flatbed scanner, but rely on the user to move them instead of a motorized belt. This type of scanner typically

does not provide good image quality. However, it can be useful for quickly capturing text.

OPTICAL CHARACTER RECOGNITION

OPTICAL MARK RECOGNITION:

Mark Sensing device The process of capturing human-marked data

from document forms such as surveys and tests.

 It is a device designed to read carefully placed pencil marked answers placed on a form or document.

MICR READER Magnetic Ink Character Recognition,

or MICR, is a character recognition technology used primarily by the banking industry to facilitate the processing of cheques and makes up the routing number and account number at the bottom of a check.

MICR (magnetic ink character recognition) is a technology used to verify the legitimacy or originality of paper documents, especially checks.

RFID READER: Radio-frequency identification (RFID)

is a technology that uses radio waves to transfer data from an electronic tag, called RFID tag or label, attached to an object, through a reader for the purpose of identifying and tracking the object. 

The RFID tag includes a small RF transmitter and receiver. 

MAGNETIC STRIPE CARD READER

Magnetic stripe card/ swipe card /magstripe:is a type of card capable of storing data on a

band of magnetic material on the card. It reads the magnetic stripe on the back of

credit cards and bank cards. It is used to identify user, account no, card

expiry, country, Card issuing company The magnetic stripe, sometimes, is read by

physical contact and swiping past magnetic reading head.

BIOMETRIC INPUT DEVICES:

Biometrics are automated methods of recognizing a person based on a physiological or behavioral characteristic. 

Among the features measured are; facial patterns, fingerprints, hand geometry, handwriting, iris, retinal, vein, DNA, and voice.

Biometric device converts personal characteristic in digital code stored in computer.

BIOMETRIC INPUT DEVICES: Finger Print reader Facial recognition system Hand geometry system Voice verification system Signature verification system Iris recognition system Line of sight Systems