Input & Output devices, Exercises of Communication

Download Input & Output devices and more Exercises Communication in PDF only on Docsity! Lozrning OO i In this chapter you will learn about: § Input/Output (I/O) devices § Commonly used input devices § Commonly used output devices § Other concepts related to I/O devices § § § § § § § Keyboard devices Point-and-draw devices Data scanning devices Digitizer Electronic cards based devices Speech recognition devices Vision based devices Seay oor Ye § Allow data entry into a computer system by pressing a set of keys (labeled buttons) neatly mounted ona keyboard connected to a computer system § 101-keys QWERTY keyboard is most popular OY arp }- Backspace cB her TPrete.¢ 921] Click buttons Ball to be rolled with fingers Commonly used in laptop (notebook) computers Click button Stick Light oe Ball indicator Socket Commonly used for video games, flight simulators, training simulators, and for controlling industrial robots Sloctroni § Pen-based point-and-draw device § Used to directly point with it on the screen to select menu items or icons or directly draw graphics on the screen § Can write with it on a special pad for direct input of written information to a system § Pressure on tip of a side button is used to cause same action as right-button-click of a mouse § Input device that translates paper documents into an electronic format for storage in a computer § Electronic format of a scanned image is its bit map representation § Stored image can be altered or manipulated with an image-processing software Two Gommor A flat-bed scanner A hand-held scanner § Scanner equipped with a character recognition software (called OCR software) that converts the bit map images of characters to equivalent ASCII codes § Enables word processing of input text and also requires less storage for storing the document as text rather than an image § OCR software is extremely complex because it is difficult to make a computer recognize an unlimited number of typefaces and fonts § Two standard OCR fonts are OCR-A (American standard) and OCR-B (European standard) § Scanner used for reading (decoding) bar-coded data § Bar codes represent alphanumeric data by a combination of adjacent vertical lines (bars) by varying their width and the spacing between them § Scanner uses laser-beam to stroke across pattern of bar code. Different patterns of bars reflect the beam in different ways sensed by a light-sensitive detector § Universal Product Code (UPC) is the most widely known bar coding system Oo Product category character 0 -— grocery products 3 — drugs and health related || — products, etc. 21000 67520 \——/ \___/ Manufacturer/supplier 7 oS identification number Specific product code number § MICR is used by banking industry for faster processing of large volume of cheques § Bank’s identification code (name, branch, etc.), account number and cheque number are pre-printed (encoded) using characters from a special character set on all cheques § Special ink is used that contains magnetizable particles of iron oxide § MICR reader-sorter reads data on cheques and sorts them for distribution to other banks or for further processing _ ° Eo . a) £3 2 ox ~ so oO & 2 Oo 353 8 2 Zo Qa = o yO - HS oO ° Cc ‘N > Qa OPO var SRR OOO QOKKS QQOOOQOO OOS DOOOKNS 09555 OO OKES QQ OOP OOOOOOO SSP ROO ROO RRS O35 5550 RRQ OOOO Electronic cards are small plastic cards having encoded data appropriate for the application for which they are used Electronic-card reader (normally connected to a computer) is used to read data encoded on an electronic card and transfer it to the computer for further processing Used together as a means of direct data entry intoa computer system Used by banks for use in automatic teller machines (ATMs) and by organizations for controlling access of employees to physically secured areas § Input device that allows a person to input datatoa computer system by speaking to it § Today’s speech recognition systems are limited to accepting few words within a relatively small domain and can be used to enter only limited kinds and quantities of data Vision-Fr § Allow computer to accept input just by seeing an object. § Input data is normally an object’s shape and features in the form of an image § Mainly used today in factories for designing industrial robots that are used for quality-control and assembly processes § Monitors § Printers § Plotters § Screen image projector § Voice response systems iyoessor © i § Soft-copy output § Not produced on a paper or some material that can be touched and carried for being shown to others § Temporary in nature and vanish after use § Examples are output displayed on a terminal screen or spoken out by a voice response system § Hard-copy output § Produced on a paper or some material that can be touched and carried for being shown to others § Permanent in nature and can be kept in paper files or can be looked at a later time when the person is not using the computer § Examples are output produced by printers or plotters on paper § Cathode-ray-tube (CRT) monitors look like a television and are normally used with non-portable computer systems § Flat-panel monitors are thinner and lighter and are commonly used with portable computer systems like notebook computers. Now they are also used with non- portable desktop computer systems because they occupy less table space. Printars Most common output devices for producing hard-copy output Character printers that form characters and all kinds of images as a pattern of dots Print many special characters, different sizes of print and graphics such as charts and graphs Impact printers can be used for generating multiple copies by using carbon paper or its equivalent Slow, with speeds usually ranging between 30 to 600 characters per second Cheap in both initial cost and cost of operation § Character printers that form characters and all kinds of images by spraying small drops of ink on to the paper § Print head contains up to 64 tiny nozzles that can be selectively heated up in a few micro seconds by an integrated circuit register § To print a character, the printer selectively heats the appropriate set of nozzles as the print head moves horizontally § Can print many special characters, different sizes of print, and graphics such as charts and graphs (Continued on next slide) Insjot Pris i (Continued from previous slide..) § Non-impact printers. Hence, they cannot produce multiple copies of a document in a single printing Can be both monochrome and color Slower than dot-matrix printers with speeds usually ranging between 40 to 300 characters per second More expensive than a dot-matrix printer § Line printers that print one line at atime § Consist of a metallic chain/band on which all characters of the character set supported by the printer are embossed § Also have a set of hammers mounted in front of the chain/band in such a manner that an inked ribbon and paper can be placed between the hammers and the chain/band Can only print pre-defined sets of characters that are embossed on the chain/band used with the printer Cannot print any shape of characters, different sizes of print, and graphics such as charts and graphs Are impact printers and can be used for generating multiple copies by using carbon paper or its equivalent Are usually monochrome Typical speeds are in the range of 400 to 3000 lines per minute Page printers that print one page at atime Consist of a laser beam source, a multi-sided mirror, a photoconductive drum and toner (tiny particles of oppositely charged ink) To print a page, the laser beam is focused on the electro statically charged drum by the spinning multi-sided mirror Toner sticks to the drum in the places the laser beam has charged the drum’s surface. Toner is then permanently fused on the paper with heat and pressure to generate the printer output Laser printers produce very high quality output having resolutions in the range of 600 to 1200 dpi (Continued on next slide) Plotiars - § Plotters are an ideal output device for architects, engineers, city planners, and others who need to routinely generate high-precision, hard-copy graphic output of widely varying sizes § Two commonly used types of plotters are: — Drum plotter, in which the paper on which the design has to be made is placed over a drum that can rotate in both clockwise and anti-clockwise directions — Flatbed plotter, in which the paper on which the design has to be made is spread and fixed over a rectangular flatbed table Paper Design drawn on the paper Design drawn on the paper Paper (Continued from previous slide..) § Produce audio output by selecting an appropriate audio output from a set of pre-recorded audio responses § Applications include audio help for guiding how to operate a system, automatic answering machines, video games, etc. § Converts text information into spoken sentences § Used for applications such as: § Reading out text information to blind persons § Allowing those persons who cannot speak to communicate effectively § Translating an entered text into spoken words in a selected language (Q? CO? (Or (Or (OD (OD COD COD CO) (OD (OD (OD CO? CO? CO? CO? CO? Bard code reader Cathode Ray Tube (CRT) Chain/ Band printer Data scanning device Digitizer Digitizing tablet Dot-Matrix printer Drum plotter Drum printer Electronic card reader Electronic Pen Flatbed plotter Flatbed Scanner Graphical User Interface Hand-held scanner Hard-copy output Image Scanner (Or (Or (Or (Or (Or (OD (OD CO) (OD 60? CO? CO? CO? CO? CO? CO? CO? Information Kiosk Inkjet printer Input/Output device Joy stick Keyboard device Laser printer Magnetic-Ink Character Recognition (MICR) Monitor Mouse Optical Character Recognition (OCR) Optical Mark Reader (OMR) Peripheral device Phonemes Plotter Point-and-draw device Printer QWERTY keyboard Screen Image Projector (Continued on next slide)