Identifying Input / Output Devices A computer input / output (I/O) devices allows communication between the user and the computer. There are three classifications of I/O devices: Input Devices: send information to the computer. E.g.: Keyboard, mouse, trackball, or scanner.

Identifying Input / Output Devices (Cont.) Output Devices: Display/Transmit information from the computer. E.g.: monitor, printer, or speakers. Communication Devices: Communicate between computers. E.g.: modems and networks.

Monitor The monitor is an output device similar to television set that allows you to view the information the computer displays. The output from a monitor is considered a soft copy while a printer’s output is considered hard copy.

Monitor Characteristics Size: its measured by inch unit, which represents the length of the diagonal. The larger the screen size the more expensive the monitor will be. Resolution: its measured in (dot pitch), resolution represents the monitor’s ability to display images to particular mathematical levels of sharpness and clarity.

Monitors Types Cathode Ray Tube (CRT) Monitor: Its cheap but has a large size. Liquid Crystal Display (LCD) Monitor: its more expensive than CRT.

Video Cards In order for the monitor to display information, it needs to be connected to a video card which contains memory to handle graphics.

Keyboard

Keyboard The keyboard is an input device, similar to a typewriter, which allows you to send information and instruction to the computer. The keyboard pad is used to reduce or prevent stress on the wrists.

Mouse and Trackball The mouse is a device used to move the pointer around on the monitor. This also applies for the trackball. The mouse has two buttons that you will use to select and activate features on the screen.

Mouse Commands Click: the left mouse button is used to select an item on the screen. Double Click: Clicking the left mouse button twice in rapid succession is used to initiate programs and open files. Right Click: is used to display the shortcut menu for an item. Left Drag: is used to move items or select multiple items on the screen.

Mouse Commands (Cont.) Right Drag: is used to move or copy items. Middle Wheel: some mice has a middle wheel that is used to scroll up or down. Thumb Buttons: some mice has a thumb button that is customized to perform specific tasks, e.g. start a program, work as alternate to Ctrl key, etc…

Other I/O Devices Digitized or Graphics Tablets: its an input device that is designed to handle graphics design work.

Other I/O Devices Microphone: is an input device that allows you to record sound and convert them into digital format. Its also used as a method of inputting information using specialized software called voice recognition

Other I/O Devices Speakers: output device that allows to play the sounds saved as digital files on the computer. Joystick: Input device that is designed for use with games.

Other I/O Devices Scanner: is an input device that allows to take a picture of the original item and then converts it into digital format. The Optical Character Recognition (OCR) software used to converts images of text into editable version.

Other I/O Devices Digital Camera: allows you to take pictures that are automatically captured as digital files. You can connect it directly to a photo printer or a compact flash reader where you can store pictures.

Other I/O Devices Digital Video Camera or Converters: allow you to take video captured with a video camera and convert it into digital files.

Other I/O Devices Bar Code Reader: is an input device that is very common in retail stores. This device reads the UPS product code.

Other I/O Devices Projector: is an output device that is used to display information with or without the monitor. Its used to deliver presentations to a large audience. In order to facilitate the presentations, you may use remote control that has been programmed to recognize the commands on the projector.

Recognizing Ports Ports are connection plugs at the back of a computer that allow you to connect an I/O device. Ports are categorized into these types: Parallel Ports: are generally used for connecting printers.

Recognizing Ports Serial Ports: Used for connecting a mouse or a modem. SCSI (Small Computer System Interface) Ports: are used to connect devices that have high performance requirement such as a CD writer.

Recognizing Ports USB (Universal Serial Bus) Ports: are used to connect newer models of devices such as mouse, modem, keyboard, scanner, etc… Network or Internet Ports: look like telephone jacks. These ports allows you to connect either to another computer on a network, a modem or the internet directly.

Printers Printers are output devices that makes hard copy (on papers) of computer files. There are different types of printers available for purchase. The one you choose will depend on your needs.

Printers Characteristics Speed: measured by cps, (character per second), or ppm, (page per minute). Resolution: measured by dpi, (dot per inch). It is the measurement of printing quality. Initial Cost: the price of the printer. Consumables Cost: the price of consumables (Papers, and ink). Printing Colors.

Types of Printers Dot Matrix: noisy printer consists of print head constructed with matrix of pins that “hammer” onto the ink ribbon to print text and graphics. The speed is about 192 (cps), and the resolution is about 180 (dpi). The initial cost is cheap and the consumables cost is low. It’s Black and white only.

Types of Printers Inkjet Printer: it has tiny nozzles in the print head. Droplets of ink are injected through the nozzles directly onto the paper and dried instantly. The speed is about 3 (ppm) or 230 (cps), and the resolution is between 300 and 1200 (dpi). The initial cost is cheap and the consumables cost is high. It’s black and white or colored.

Types of Printers Bubble Printers: The same as Inkjet with the only difference that the ink is pushed out of the nozzles by expanding bubbles.

Types of Printers Laser Printer: Uses the same laser beam electrostatic printing method on which the office photocopier is based. The speed is very high, and the resolution is between 300 and 1200 (dpi). The initial cost is the highest and the consumables cost is low per page. It’s black and white or colored but color printing can be expensive.

Miscellaneous Types of Printers All in one: it is a combination of general office devices; like printer, scanner, copier, and fax. Photo Printer: designed to be able to connect directly with the digital camera to print directly onto the photo paper.

Miscellaneous Types of Printers Plotters: another types of printers that prints images onto a very large pieces of paper like posters.

Networks Microcomputers are often linked together to form a network which allows many users to access to the same data. Network is a system that allows two or more computers to communicate and share resources with each other.

Networks Each computer requires a Network Interface Card (NIC) and the appropriate cables to connect it to a dedicated computer called a network server.

Networks Mainframe computers generally store customized software applications and large amounts of data. A client/Server Network has PCs (Personal Computers) connected that can function on their own as well as connect to the server to access information.

Types of Networks LAN (Local Area Network): A network that connects a small to medium number of computers in a confined area. WAN (Wide Area Network): A network connecting computers over long distances. E.g. between branches in different provinces.

Types of Networks MAN (Metropolitan Area Network): A network connecting computers in a metropolitan area. CAN (Campus Area Network): A network connecting computers in limited area such as a campus or military base. HAN (Home Area Network): A network connecting computers in a home environment

Networks Benefits The main benefit for networks is the ability to share resources such as data files, software applications, printers, and internet connection.

Interacting with Networks When your computer has been set up to recognize the network (Server), you can log into the network.. This generally requires a user account (ID and Password) which set up by the network administrator.