Input and Output Devices

Input and Output DevicesAshley-Ann Cooper, Stephan Pitterson, Russell Coke, Briana Douglas, Kode Williams6B.1#TEAMOrgaNiceWhat is an input device?An input device is any technology used to get information from the outside world into the computer for processing.There are two types of input devices: manual and direct.Manual Input DevicesA manual input device:Is a hardware or peripheral device Used to communicate and feed instructions and data into the computerfor processing, display, storage user must enter or transfer data into the computer by hand.ExamplesKeyboard: one of the most common manual input devices.Used to type commands and instructions into the computer.Has a set of alphanumeric keys, and function keys Convert keystrokes into binary digits, Carries out the commands of function keys

ExamplesMouse: also one of the most common manual input devices.The most common pointing input device. It sends positional information to the computer my clicking or scrolling of the mouse buttons.Has two buttons: the left is usually used to select items and the right to access menus.There are two types of mice: mechanical and optical.

ExamplesJoystickSimilar in appearance to a vehicle hear shift, but has buttons which carry out different commands.Generally used for playing video games and in virtual reality simulations and robot control.

ExamplesTouch screenAllows the user to press parts of the screen with their fingers or a stylus in order to activate commandsThere is no need for a keyboard or mouse with a touchscreen

Direct Input DevicesDirect input devices: convert data directly from the source into a format the computer can understand. Doesnt require user to manually input the data. They reduce the chance of data entry errors, as the user needs not worry about entering data incorrectly.ExamplesScannerAllows the transfer of pictures, graphics and text to the computer by scanning the image from top to bottom, one line at a time, and transfers it to the computer.Used to capture a hard-copy of an image and create a digital copy of it.Usually connected via USB which transfers data at 20-60Mb/s.The resolution of the scanner varies; high end scanners have a resolution of up to 24000 pixels per inch.

ExamplesMicrophoneData is input in audio formCommonly used in voice recognition software: users can dictate or give commands directly to the computer without the need for typing or clicking.Can be connected to the computer via USB or through the microphone port. Some computers come with microphones built in, as do most webcams.

ExamplesMagnetic Ink Character RecognitionReads data printed in special magnetic ink and converts it into a computer readable form.Commonly used by banks on cheques.Connect to the computer via PS2 Y port.

What is an output device?An output device is any technology used to present information from the computer to the user.There are two types of output: hard copy and soft copy.Hardcopy OutputHardcopy output refers to physical output from the computer: recording letters, graphics or pictures on a permanent medium such as paper or film.Modern output devices are fairly fast, the fastest printer being able to print up to 500 pages in just over 7 minutes.The quality of the output varies depending on the type of device; the highest quality device on the market are film recorders, outputting at least 4,000dpi (dots per inch) versus a standard ink jet printer which outputs about 600dpi.PrintersPrinters are the most common type of hardcopy output devices. They print information from the computer onto paper. There are two types of printers: impact and non-impact.Impact PrintersImpact printers work by striking a carbon/inked ribbon onto paper. They have very low resolutions and are incapable of printing graphics. They are slow and very noisy, as the process is purely mechanical. However, some line printers are very fast, capable of printing 1500 lines per minute, hence their usage in printing mass bills, address labels, etc.

Non-Impact PrintersMost printers used today are non-impact printers. These printers do not strike the paper, but instead spray ink or toner powder onto it. Heat is then used to fix the characters onto the paper.Three types of non-impact printers are ink jet printers, laser printers, and thermal printers.Ink Jet PrintersInk jet printers produce small ink droplets and move them around electrostatically. Speeds of 4-6 pages per minute can be achieved.Resolution varies greatly as different printers have different capabilities, and the colour being printed also affects the quality. Standard ink jet printers have resolutions of 600*600 dpi (dots per inch).Laser PrintersLaser printers work by producing charges on the paper that attract dry ink powder. The pattern is then heated to fix it on the page. Resolutions tend to call between 300 and 1200 dpi.Speeds of 4 to 20 pages per minute are common.

Thermal PrintersThermal printers use heat on chemically treated paper to make characters. These are common in ATM machines to print receipts and in some ultrasound machine printouts.PlottersPlotters are specialized type of printer. They are used by designers, engineers, and architechs to print accurate charts, 3D drawings, blueprints, etc. The use coloured pens or toner to draw the images on the paper.They can print up to 500 sq ft/hour.They have a standard resolution of 1200x600dpi.

Soft Copy OutputSoft copy output refers to devices that feed information to the user through the use of a temporary output device.Softcopy devices include monitors, speakers, headphones and projectors.How are they connected to the computer?Modern visual softcopy output devices usually used HDMI ports to connect to computers, as HDMI provides the best definition, speed colour, and sound.Speakers are connected either by Wifi, Bluetooth, or audio jacks. The standard size of an audio jack is 3.5mm.Older projectors and monitors use VGA (Video Graphics Analog) connectivity. This is the oldest type of connectivity for these devices and provides the lowest speed and quality, as the digital data from the computer has to be converted to analog data for transmission, so quality is lost.Specialized DevicesThese are not typical input/output devices. They are used by people who are disabled, or have special occupations.Specialized Devices : Braille DevicesBraille is the writing system for blind persons.Braille keyboard: similar to a regular keyboard, but keys are embossed in braille rather than printed in English characters.Braille display/terminal: a monitor for blind people. It works by raising round pins in patterns to resemble braille characters.Braille printers: a type of impact printer which prints embossed onto paper. Normally, a braille translation software is used to convert English characters to braille.Other Specialized DevicesSpeech Synthesizers: Used to convert text, or other input, into digital signals, which are then converted into text. The most common is TTS (Text-To-Speech) devices.Virtual Reality devices: Used by designers to create a virtual reality in which they can see how their product would work in the real world. It also allows them to modify the design before building the final product.There are also rumoured devices which can convert brain activity into digital signals, which would be used by disabled people who have no way of entering data manually.