These are devices used for entering data into the computer using a set of keys. The keying devices converts typed numbers, letters and special characters into machine readable form before processing takes place. They include the keyboard, the key-to-storage and the keypad.
1.Keyboard
A keyboard is a device that converts letters, numbers and other characters into electrical signals that are machine-readable, so that they can be recognized by the computer processor. The keyboard is used to enter textual data.
Types of keyboard
- Traditional keyboard; Is the most common type of keying device.
- Flexible keyboard; Is more portable and can be folded and packed into a bag.
- Ergonomic Keyboard; Is specially designed to provide comfort and alleviate wrist strain.
- Braille keyboard; Is a keyboard designed for use by the blind. It consists of keys identified by raised dots.
- Keypad; This are small /miniature keyboard which are mostly used on portable computers such as palmtops, laptops, mobile phones and PDAs.
Most computer keyboards follow the QWERTY order, which refers to the sequence of the alphabetic keys on the top left row on a standard keyboard. Another keyboard layout is the AZERTY, which is common in European countries.
During the typing in process, the keyed data and instructions are displayed on the screen. They are sent as electric signals to the CPU through electrical pathways called buses where they are digitized, that is, converted to digital data. They are then displayed back on the screen in human readable characters, that is, converted to analog data.
- Key-To-Storage(Offline)Input Devices
In the key-to-store method, data are input directly, saved or stored in a hard disk, a magnetic tape or a diskette.
