INFS 214: Introduction to Computing · scan the image of a document converting the light and dark...

College of Education

School of Continuing and Distance Education 2014/2015 – 2016/2017

INFS 214:

Introduction to Computing

Session 5 – Output Technologies

Lecturer: Dr. Ebenezer Ankrah, Dept. of Information Studies Contact Information: [email protected]

Session Overview

• Output technologies consist of devices that translate information processed by computer systems into a form that humans can understand.

• The electronic-based information consists of 0s and 1s, which need to be translated into words, numbers, sounds and pictures.

• This session explains the types and categories of output devices that are used in the computer environment.

DR. EBENEZER ANKRAH Slide 2

Session Overview

• At the end of the session, the student will

– Understand and differentiate between the various types of output devices

– Be able to give examples of output devices

– Understand the different features of monitors

– Be able to identify the components of some of the output devices

– Be able to differentiate between various input and output combination devices


Session Outline

The key topics to be covered in the session are as follows:

• Introduction to Output Devices

• Display Devices

• Printers

• Combination Devices


Reading List

• Hutchinson, S. E., & Sawyer, S. C. (2013). Computers: The user perspective. Boston: Irwin McGraw-Hill. (Chapter 6)

• O’Leary, T. J., & O’Leary, L. I. (2014). Computer Today. Boston: McGraw Hill. (Chapter 8)

• Williams, B. K., & Sawyer, S. C. (2014). Using Information Technology: A practical introduction to computers and communications (11th ed.). McGraw-Hill Education. (Chapter 6)


INTRODUCTION TO OUTPUT DEVICES

Topic One


Introduction to Output Devices

• Devices that display, print, or transmit the results of processing from the computer’s memory are called input devices.

• Before an output can be produced by a computer it must have an output device connected to it. Output (as a noun) is used to describe information transmitted from a computer.

• The process by which information is shown by the computer system after processing is also termed output (as a verb).



• Output devices are various devices used to view information from a computer system. Output is data that has been processed into a useful form. Computers process data (input) into information (output).

• A computer generates several types of output, depending on the software being used and the requirements of the user.

• While working on the computer, a user encounters four basic categories of output: text, graphic, audio and video. Very often, a single form of output such as a Web page includes more than one of the categories.



• Output technology trends

• Output technology trends show a move from paper documents to more natural forms of video, audio, and multimedia, for natural, quicker and clearer communication.



Generation Output Method/Media

1st Generation Punched cards, Printed reports and documents

2nd Generation Punched cards, Printed reports and documents

3rd Generation Printed reports and documents, video displays

4th Generation Video displays, audio responses, printed reports

and documents

5th Generation Video displays, voice responses, hyperlinks

multimedia documents


Questions

• Individual Assignment:

– List some of the input and output combination devices

• Forum Question:

– Discuss the features of monitors


DISPLAY DEVICES Topic Two


Display Devices

• Display devices are hardware components that visually display the result of data that has been processed. The output from display devices are often referred to as soft copy.

• The main display device is a monitor. They are the most frequently used output device. Monitors are also known as display screens or simply as screens.

• Monitors present visual images of text and graphics. Monitors vary in size, shape, and cost. Almost all, however, have some basic distinguishing features. The monitor displays computer output.


Display Devices

• The monitor displays the video and graphics information generated by the computer through the video card. Monitors are very similar to televisions but usually display information at a much higher resolution.

• The most important characteristic of a monitor is its clarity. Clarity refers to the quality and sharpness of the displayed images. It is a function of several monitor features.


Display Devices

• The features of monitors are:

– Resolution,

– Dot pitch,

– Refresh rate,

– Pixel and

– Size.


Display Devices

• Resolution

– Images are formed on a monitor by a series of dots or pixels (picture elements). Resolution is expressed as a matrix of these dots or pixels.

– For example, many monitors today have a resolution of 1,280 pixel columns by 1,024 pixel rows for a total of 1,310,720 pixels.

– The higher a monitor's resolution (the more pixels) the greater the clarity of image produced. Over the years, several video standards have been developed to define the resolution, number of colors, and other display properties.


Display Devices

• Current Video Standards include:

– SVGA (Super Video Graphics Array), which has a resolution of 800 × 600;

– XGA (Extended Graphics Array), a resolution of 1024 × 768;

– SXGA (Super XGA), a resolution of 1280 × 1024;

– UGA (Ultra XGA), a resolution of 1600 × 1200.


Display Devices

• Dot pitch – It is the distance between each pixel. Most newer monitors

have a dot pitch of 0.31 mm (31/100th of a millimetre) or less. The lower the dot pitch (the shorter the distance between pixels), the higher the clarity of images produced

• Refresh rate – Refresh rate indicates how often a displayed image is

updated or redrawn on the monitor. Most monitors operate at a rate of 75 hertz, which means that the monitor is redrawn 75 times each second.


Display Devices

• Images displayed on monitors with refresh rates lower than 75 hertz appear to flicker and can cause eye strain. The faster the refresh rate (the more frequently images are redrawn), the better the quality of images displayed.


Display Devices

• Size – Size or viewable size is measured by the diagonal length of

a monitor's viewing area. Common sizes are 15, 17, 19, and 21 inches. The smaller the monitor the better the quality of images displayed.

• Types of Monitors are: – Cathode-Ray Tube

– Flat-Panel Monitors

– Light-Emitting Diode

– Other Monitors (E-books, Data Projectors and HDTV)


PRINTERS Topic Three


Printers

• Printers translate information that has been processed by the system unit and present the information on paper or other types of material.

• Printer output is often called hard copy. There are many different types of printers. Almost all, however, have some basic distinguishing features including: Resolution, Colour, Speed and Memory.


Printers

• Resolution – Resolution of a printer is similar to monitor resolution. It is a

measure of the clarity of images produced. Printer resolution, however, is measured in dpi (dots per inch).

– Most printers designed for personal use average 1200 dpi. The higher the dpi, the better the quality of images produced.

• Colour

– It is provided by most printers today. Because it is more expensive to print in colour, most users select black ink for letters, drafts, and home work. Colour is used more selectively for final reports containing graphics and for photographs.


Printers

• Speed – It is measured in the number of pages printed per minute.

Typically, printers for personal use average 10 to 15 pages per minute for single colour (black) output and 5 to 10 pages per minute for colour output.

• Memory – It is within a printer and it is used to store printing

instructions and documents waiting to be printed. The more memory in a printer, the faster it will be able to create large documents.


Printers

• Types of Printers • The main types of printers are Ink-Jet Printer, Laser

Printer, Thermal Printer. Other Printers are Dot-matrix printers, Plotters and Photo printers

– Ink-Jet Printer

– Ink-jet printers spray ink at high speed onto the surface of paper. This process not only produces a letter-quality image but also permits printing to be done in a variety of colours making them ideal for select special applications.


Printers

– Ink-jet printers are the most widely used printers. They are reliable, quiet, and relatively inexpensive. The most costly aspect of ink-jet printers is replacing the ink cartridges. Typical ink-jet printers produce 17 to 19 pages per minute of black-only output and 13 to 15 pages of colour output.


Printers

– Laser Printer

– Laser printers use a laser light beam to produce images with excellent letter and graphics quality. More expensive than ink-jet printers, laser printers are used in applications requiring high-quality output. There are two categories of laser printers:

• Personal laser printers typically do not support colour, are less

expensive, and are used by many single users. They typically can print 15 to 17 pages a minute.

• Shared laser printers typically support colour, are more expensive,

and are used (shared) by a group of users. Shared laser printers typically print over 50 pages a minute


Printers

– Thermal Printer – A thermal printer uses heat elements to produce images on heat

sensitive paper. Originally these printers were only used in scientific labs to record data. More recently, colour thermal printers have been widely used to produce very high-quality colour artwork and text.

– Colour thermal printers are not as popular because of their cost and the requirement of specially treated paper. They are a more special-use printer that produces near-photo-graphic output. They are widely used in professional art and design work where very high-quality colour is essential.

– Other Printers – Examples of other printers are Dot-matrix printers, Plotters and Photo

printers


COMBINATION DEVICES Topic Four


Combination Devices

• Combination Devices

• Combination devices have functionalities of both input and output devices. The following are combination of input and output devices: Fax Machines, Multifunctional Devices, Internet Telephone and Terminals.

– Fax Machines

– A fax machine, also known as a facsimile transmission machine, is a standard tool in nearly every office. To send a fax, these devices scan the image of a document converting the light and dark areas into a format that can be sent electronically over standard telephone lines. To receive a fax, these devices reverse the process and print the document (or display the document on your monitor) using signals received from the telephone line.


Combination Devices

– Multifunctional Devices

– Multifunctional devices (MFD) typically combine the capabilities of a scanner, printer, fax, and copying machine. These multifunctional devices offer a cost and space advantage. They cost about the same as a good printer or copy machine but require much less space than the single-function devices they replace.


Combination Devices

– Internet Telephone

– Internet telephones are specialized input and output devices for receiving and sending voice communication. Typically, these devices connect to the system unit through a USB port and operate much like a traditional telephone.

– Telephony is the transmission of telephone calls over computer networks. Internet telephony, IP Telephony, and Voice-over IP (VoIP), telephony uses the Internet rather than traditional communication lines to support voice communication. To place telephone calls using telephony requires an Internet telephone (or other appropriate input and output devices), an Internet connection, sound card, and special software.


Combination Devices

– The two most popular applications are:

• Computer-to-computer communications

• Computer-to-traditional telephone communication

– Terminals

– In large computer systems several people are capable of working on the same computer at the same time. In this case, some of the devices like processor and memory are shared. Devices that are not shared are placed at several points of access to the computer.


Combination Devices

– These points (stations) are called terminals. An input device may be part of a terminal that is connected to a large computer. A terminal includes:

• An input device (a keyboard, mouse, or wand reader for instance)

• An output device (monitor or screen),

• A connection to the main computer.

– There are four types of terminals and these are dumb terminal, intelligent terminal, network terminal and internet terminal.


References

• Hutchinson, S. E., & Sawyer, S. C. (2013). Computers: The user perspective. Boston: Irwin McGraw-Hill.

• O’Leary, T. J., & O’Leary, L. I. (2014). Computer Today. Boston: McGraw Hill.

• Williams, B. K., & Sawyer, S. C. (2014). Using Information Technology: A practical introduction to computers and communications (11th ed.). McGraw-Hill Education.


INFS 214: Introduction to Computing · scan the image of a document converting the light and dark...

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