Key code

What does Key code mean?

A key code is a unique numerical identifier assigned to each key on a computer keyboard or other input device, such as a mobile phone or remote control. It represents the physical location and function of the key, allowing the operating system or application to determine which action should be taken when the key is pressed.

Key codes are typically composed of three parts: the scan code, the make code, and the break code. The scan code identifies the physical location of the key, While the make code and break code indicate when the key is pressed and released, respectively. This information is sent to the operating system or application, which then triggers the appropriate action associated with that key.

For Example, when the “A” key on a keyboard is pressed, the operating system receives the scan code for the “A” key, along with the make code. The operating system then interprets this input and sends a command to the application, such as a text Editor, to insert the letter “A” into the document.

Key codes are essential for the proper functioning of computer systems and other electronic devices that rely on input from keyboards or other input devices. They allow the operating system to identify and process keystrokes efficiently, enabling users to control and interact with the system effectively.

Applications

Key codes have a wide range of applications in technology today, including:

Input Processing: Key codes are used by operating systems and applications to process input from keyboards and other input devices. This includes recognizing which keys are pressed, when they are pressed, and when they are released.

Keyboard mapping: Key codes are used to map physical keyboard keys to specific functions or actions. This allows users to customize their keyboards and assign different functions to different keys.

Assistive Technology: Key codes are used by assistive technology software to provide alternative input methods for people with disabilities. For example, a screen reader may use key codes to identify and announce the text that appears under a mouse cursor.

Remote Control: Key codes are used in remote controls to transmit commands to electronic devices, such as televisions, audio systems, and DVD players. Each button on a remote control corresponds to a specific key code, which is sent to the device when the button is pressed.

Security: Key codes are sometimes used as a security measure to restrict access to certain devices or applications. For example, a mobile phone may require the user to enter a key code or password before it can be used.

History

The concept of key codes dates back to the early days of computing. One of the first systems to use key codes was the Teletype Model 33, which was introduced in 1963. The Teletype Model 33 used a 5-bit key code to represent each character or control function.

As computer systems evolved, so did the concept of key codes. In the early 1980s, the IBM PC introduced the extended keyboard, which included additional function keys and other Special keys. This led to the development of more complex key codes to represent the expanded range of functions.

Today, key codes are an integral part of all modern computer systems and electronic devices. They provide a standardized way to represent keyboard input and enable the efficient processing of keystrokes.