CIT 1100
In this chapter you will learn how to - Describe the workings of keyboards Explain how to connect and use mice and other pointing devices Describe how to work with monitors
The standard computer uses two types of input devices and one output device Keyboard Mouse Monitor enables the computer to show you the results of those commands Monitor enables the computer to show you the results of those commands Less common I/O devices include: ◦ Printers ◦ Speakers ◦ Touch-screen ◦ Microphones
The keyboard enables you to communicate with the processing parts of the computer You can enter commands that the computer understands even if you don't have an operating system Applications including the OS, supports specific keyboard commands Keyboard is the primary input device for all personal computers and many computing devices Manufacturers have added extra keys to the standard keyboard, but most still have the same basic keys Keyboards in English-speaking countries all have the same layout, called QWERTY Function keys can change a lot depending on the program, but Fl is almost always Help
Keyboards use two basic connectors to plug into a computer The old style is called a mini-DIN or PS/2 connector. It is round, with six pins and a small tab so that you can only insert it one way PS/2 connectors are still very common. Some motherboards color the keyboard PS/2 socket purple MOST newer keyboards use a rectangular USB connector USB connectors are keyed so that you can't plug them in incorrectly
Most operating systems come with a utility that allows the user to make adjustments to the keyboard
Mice and other pointing devices enable you to move a cursor around the screen and select things Mice designed for Windows computers traditionally have two buttons You can left-click to select something on the screen Right-clicking gets you information about whatever you click Double-left click to tell Windows to do something with whatever you select
Many current mice have a scroll wheel in the center that enables you to move up and down in a window When you're on a Web page, for example, you can scroll up and down by clicking the arrows on the right side of the page or by rotating the wheel Mice use one of two connectors to plug into a computer just like the keyboard Older mice use a mini-DIN or PS/2 connector, the mouse port is green Most mice today connect via USB
Mice originally came with a ceramic ball that tracked the movement and translated that to the computer Older ball mice collected dust and grime on the sensors and have to be cleaned periodically Newer optical mice use a red light to track movement, they don't have to be cleaned Trackballs have buttons and wheels, just like mice. Trackballs are great when you don't have a normal table on which to work or when you have wrist difficulties
The primary output device for the computer It displays results of input and the computer's processing Advanced much since the first monochrome display devices Two varieties CRT and LCD, Cathode Ray Tube (CRT) monitors use the same technology as old televisions, LCD is the newest CRTs require extremely high voltage > 30,000 Volts LCDs consume considerably less power
CRTs contain an assortment of hazardous materials, including lead, phosphorus, and mercury, they cannot be disposed of in landfill Contact a computer recycling company to dispose of old computer components
The video card also knows as the GPU (graphics processing unit) helps the CPU and operating system change the image on the display The GPU is a processor that can rapidly access video memory which is used to create images on the CRT Specifically designed to handle computer graphics, much more efficiently than the CPU Most newer desktop and notebook computers have integrated GPUs Integrated video is not as powerful as a dedicated video card Most gamers will not use embedded video chips
The oldest connector type is the Video Graphics Array (VGA) connector It has 15 pins, laid out in three rows of five The VGA connector is used primarily by CRT monitors still used on many LCD monitors Today's most commonly used connector is the Digital Visual Interface (DVI) connector. Depending on the monitor, it can have up to 29 pins The High-Definition Multimedia Interface (HDMI) connector is unique because it is used for both video and audio signals, whereas VGA and DVl only carry video signals HDMI is found on more HD televisions than monitors, but it is becoming more popular with computers, the connector looks somewhat like USB but only fits in HDMI ports.
In addition to the physical buttons on the monitor, the Display applet in Windows also controls the appearance of the display The resolution determines the number of pixels used to create the image on the monitor, its the number of pixels across by the number of pixels down 1440 X 900 As the resolution changes so does the size of the Icons Monitors can be rotated to display in Portrait view for full page text editing