ASCIICharacter encoding standardASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English-language–focused) printable and 33 control characters – a total of 128 code points. The set of available punctuation had significant impact on the syntax of computer languages and text markup.
Computer terminalA computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. Most early computers only had a front panel to input or display bits and had to be connected to a terminal to print or input text through a keyboard. Teleprinters were used as early-day hard-copy terminals and predated the use of a computer screen by decades.
Caret notationCaret notation is a notation for control characters in ASCII. The notation assigns ^A to control-code 1, sequentially through the alphabet to ^Z assigned to control-code 26. For the control-codes outside of the range 1–26, the notation extends to the adjacent, non-alphabetic ASCII characters; for example ^@ is used for control-code 0. Often a control character can be typed on a keyboard by holding down the Ctrl and typing the character shown after the caret.
Baudot codeThe Baudot code (French pronunciation:) is an early character encoding for telegraphy invented by Émile Baudot in the 1870s. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use before ASCII. Each character in the alphabet is represented by a series of five bits, sent over a communication channel such as a telegraph wire or a radio signal by asynchronous serial communication.
UnicodeCharacter encoding standardUnicode (also known as The Unicode Standard and TUS) is a character encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world's writing systems that can be digitized. Version 18.0 defines 172,808 characters and 175 scripts used in various ordinary, literary, academic and technical contexts.EBCDICExtended Binary Coded Decimal Interchange Code (EBCDIC; ) is an eight-bit character encoding used mainly on IBM mainframe and IBMmidrange computer operating systems.Terminal emulatorA terminal emulator, or terminal application, is a computer program that emulates a video terminal within another display architecture. Though typically synonymous with a shell or text terminal, the term terminal covers all remote terminals, including graphical interfaces. A terminal emulator inside a graphical user interface is often called a terminal window.
TeleprinterA teleprinter (teletypewriter, teletype or TTY) is an electromechanical device used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Initially, teleprinters were used in telegraphy. Electrical telegraphy had been developed decades earlier in the late 1830s and 1840s, then using simpler Morse key equipment and telegraph operators.
Terminal (macOS)Terminal is the terminal emulator included in the macOS operating system by Apple. Terminal originated in NeXTSTEP and OPENSTEP, the predecessor operating systems of macOS.
Desktop environmentIn computing, a desktop environment (DE) is an implementation of the desktop metaphor made of a bundle of programs running on top of a computer operating system that share a common graphical user interface (GUI), sometimes described as a graphical shell. The desktop environment was seen mostly on personal computers until the rise of mobile computing.
Backward compatibilityIn telecommunications and computing, backward compatibility (or backwards compatibility) is a property of an operating system, software, real-world product, or technology that allows for interoperability with an older legacy system, or with input designed for such a system. Modifying a system in a way that does not allow backward compatibility is sometimes called "" backward compatibility. Such breaking usually incurs various types of costs, such as switching cost.
MacOSmacOS (previously OS X and originally Mac OS X) is a proprietary Unix operating system, derived from OPENSTEP for Mach and FreeBSD, which has been marketed and developed by Apple since 2001. It is the current operating system for Apple's line of Mac computers. As of April 2026, within the market of desktop and laptop computers, it is the second most widely used desktop OS, after Microsoft Windows and ahead of all Linux distributions, including ChromeOS and SteamOS.
Electric bellAn electric bell is a mechanical or electronic bell that functions by means of an electromagnet. When an electric current is applied, it produces a repetitive buzzing, clanging or ringing sound. Electromechanical bells have been widely used at railroad crossings, in telephones, fire and burglar alarms, as school bells, doorbells, and alarms in industrial areas, since the late 1800s, but they are now being widely replaced with electronic sounders.*As an Amazon Associate I earn from qualifying purchases.