1. What is Output?

• Output is processed data or information
• Typically takes the form of text, graphics, photos, audio, video or images.
• Output devices are any hardware used to provide or create output for the people by translating what the computer has processed into a form that people can understand and use, for example monitors, printers, speakers, etc.
• For example, when you create a presentation you usually include text and graphics and also include photographs and even ass voice narration making it a complete presentation.
• Images displayed on monitor are often referred to as softcopy.

1. Monitors

• Monitor is the most frequently used output device and is also known as display screens or screens
• Two important characteristics of monitors are: size and clarity.

1. Size: indicated by the diagonal length of its viewing area, common sizes are 15, 17, 19, 21 inches, for viewing more information a large monitor is needed but it is expensive.
2. Resolution: clarity of monitor is indicated by its resolution, measured in pixels – dots or picture elements that form images on a monitor, e.g. a 1,280 x 1,024 resolution screen displays 1,310,720 pixels, the greater the number of pixels, the better the resolution, the greater the resolution (more pixels) the better the clarity of the image.

• Dot Pitch: the distance between pixels, typically measured in millimeters.  Most monitors have a dot pitch less than 0.3 mm.  The smaller the dot pitch, the better the clarity.
• Refresh Rate: how often the image is “re-drawn” on the monitor.  Most monitors have a refresh rate of 75 Hz or better (image refreshes 75 times every second).  The faster the rate, the better the image

STANDARDS

• Standards indicate monitor’s resolution capabilities. The four most common standards today are:

• SVGA (Super Video Graphics Array) – has a minimum resolution of 800 X 600 pixels. It was most popular few years back but now it is mostly used with 15-inch monitors.
• XGA (Extended Graphics Array) – has a resolution of up to 1024 X 768 pixels. A popular standard today with 17- and 19-inch monitors.
• SXGA (Super Extended Graphics Array) – has a resolution of 1280 X 1024 pixels. A popular standard today with 19- and 21-inch monitors.
• UXGA (Ultra Extended Graphics Array) – newest and highest standard used primarily for high-end engineering design and graphics art. It will be used widely when 21-inch monitors becomes common in future.

1. Cathode-Ray Tube (CRT)

• Most common type of monitor for office and home placed directly on system unit or desktop.
• Similar in size and technology as standard TV screens
• Advantage is they are relatively of low cost and have a high quality image display.
• Disadvantage is they take up a lot of space.

1. Flat-Panel Monitor or Liquid crystal display (LCD) monitors

• They use liquid crystals.
• They are portable and take up less space (thinner) and require less power than CRTs.
• They are used both for portable computers like tablet PC, handheld computers and desktop computers.
• Two basic types are:

• Passive matrix (dual scan monitors): create images by scanning the entire screen. It requires low power, but images are of poor clarity
• Active matrix (TFT: Thin Film Transistor): They do not scan the screen instead each pixel is independently activated. It is more expensive, uses more power, but produces a much better image with more colors.

2. Other Monitors

• E-books (aka e-book readers) are hand held, book-sized devices that display text and graphics. Using content downloaded from the Web, these devices are used to read newspapers, magazines, and entire books. The time and cost of creating and distributing e-book content is less than publishing and delivering traditional print media.
• Data projectors: are similar to slide projectors that connect to microcomputer and project the output onto a screen for a large audience. Marketing people, teachers frequently use presentation graphics programs like PowerPoint to create presentations and then deliver the presentation in classrooms or boardrooms using data projectors.
• High Definition TeleVision (HDTV): a merger of microcomputers and television (PC/TV) offers much clearer and more detailed wide screen pictures than a standard TV (but currently at more cost).  Since images are digital, they can be stored and edited to create high-quality still images.

1. Printers

• Printer output (on paper) is often called hard copy.

1. Features

• Resolution: measured in Dots Per Inch (DPI), typically 300, 600, or 1,200 in modern printers.  The more dots, the better the image, but the more ink that is used.  Photo printing uses even higher dpi printers (2,400 & 4,800 dpi)

NOTE: you can save ink if you adjust the settings to a lower DPI setting –

300 or 600 DPI often works well for plain text.

• Color capability: Black & White or color
• Speed: typically measured in Pages Per Minute (ppm).  Personal printers typically print 10-15 ppm for a single color (black) and 5-10 color
• Memory: most printers have on-board RAM to buffer the print so the computer is free to do other tasks.

1. Ink-Jet Printer

• Widely used technology that sprays small droplets of ink at high speed onto the surface of paper.
• They produce letter-quality images and prints in variety of colors.
• They are relatively inexpensive, quiet, and reliable.
• They are used in advertising and public relations where color and appearance is important.

1. Laser Printer

• Uses technology similar to a photocopying machine where a laser beam is used to produce images with excellent letter and graphics quality.
• They are more expensive than ink-jet printers but produce high-quality output.
• Two qualities are:

• Personal laser printers are cheaper and used by many single users.  They typically print 4 to 6 pages in a minute.
• Shared laser printers are more expensive and used by a group of users, and print at high speeds, print over 30 pages in a minute

2. Thermal Printer

• Uses heat elements to produce images on heat-sensitive paper.
• Previously used only in scientific labs to record data but recently being used to produce very high-quality color artwork and text.
• Not as common as Ink-Jet and Laser printers because of their cost and requirement of specially treated paper.

1. Other Printers

• Dot matrix printers: form characters and images using a series of small pins on a print head, they are inexpensive and reliable but quite noisy, used for tasks where high-quality is not required.
• Chain printers: used on a network connected to serve several computers or a mainframe computer requiring large quantities of printed output. They are expensive high-speed machines.
• Plotters: using output from digitizing tables and other graphics input devices they create maps, images, architectural and engineering drawings used by architects, engineers and graphic artists They can produce high-quality, multicolor documents and also documents that are larger that other printers cannot handle.

1. Audio Output Devices

• Translate audio information from the computer into sounds that people can understand.
• Most widely used devices are speakers and headphones
• These must be connected to a sound card in the system unit.
• Creating voice output is easier than recognizing voice input, and is used for many applications such as soda machines, telephones, and cars.

1. Combination Input and Output Devices

1. Fax machines

• Also know as Facsimile Transmission Machines, it’s an older technology used to transmit a “picture” of a document over telephone lines found in almost offices.
• To send fax, these devices scan the image of a document converting light and dark areas into a format that can be sent electronically over standard telephone lines.

1. Multifunction Devices (MFD) aka All In One (AIO) devices

• These devices combine the functions of a printer, scanner, copier, and fax into one unit.
• The advantage is it can save cost over buying separate units, as well as space.
• The disadvantage is the functionality may not be as good as separate machines, and if one goes bad, you may need to replace the whole device.

1. Internet Telephone

• Internet telephones typically connect to a system unit through a USB port and operate like a traditional telephone.
• Telephony, also known as Internet telephony, IP telephony and Voice Over IP (VoIP) – Note: IP = Internet Protocol uses the Internet rather than traditional communication lines to support voice communication.
• Convert analog voice into digital, and utilizes the Internet Protocol to send the digital signals.
• This technology is proving to be a popular, cost saving tool for both businesses and home users.
• Internet supported calls may have lower sound quality.

1. Terminals

• An input and output device that connect to a mainframe or host/server computer.
• The four kinds of terminals are:

• Dumb terminals: used to input and receive data, but cannot process data independently. Used to gain access to information from a computer. May be used by airline reservations agent for flight information stored on a mainframe computer.
• Intelligent terminals (Smart terminals) include a processing unit, memory and secondary storage. It is a microcomputer with communication software and a telephone link (modem) or other communication link.  Net PC (aka Net Personal Computer) is a low cost limited microcomputer with only a hard drive, sealed system unit and no expansion slots.
• Network terminal (aka thin client or network computer) is a low cost alternative to an intelligent terminal.  Most don’t have storage capabilities and must depend on a host computer or server for application and system software.
• Internet terminal (aka Web terminal or Web appliance) provides access to the Internet and display web pages on a standard television set. These special-purpose terminals offer Internet access without a microcomputer.