Indicates the end of the storage medium (End of Medium) Makes it clear that a transmission was faulty and the data must be discarded (Cancel) Marks the end of a transmission block (End of Transmission Block) Synchronizes a data transfer, even if no signals are transmitted (Synchronous Idle) Negative response to a request (Negative Acknowledge) Switches the display back to the normal state (Shift In)Ĭhanges the meaning of the following characters (Data Link Escape)Ĭontrol characters assigned depending on the device used (Device Control) Switches to a special presentation (Shift Out) Moves the cursor back to the first position of the line (Carriage Return) The vertical tab lets the cursor jump to a predefined line (Vertical Tab) Lets the cursor move back one step (Backspace)Ī horizontal tab that moves the cursor within a row to the next predefined position (Horizontal Tab)Ĭauses the cursor to jump to the next line (Line Feed) Gives a positive answer to the request (Acknowledge) Marks the end of a completes transmission (End of Transmission)Ī request that requires a response (Enquiry) Indicates the end of the message (end of text) The null character prompts the device to do nothingĮnds the header and marks the beginning of a message.
They are used to send commands to the PC or the printer and are based on telex technology. Control Characters (0–31 & 127): Control characters are not printable characters.The ASCII characters can be divided into several groups. The ASCII-based extended versions use this exact bit to extend the available characters to 256 (2 8).Įach character corresponds to a seven-digit sequence of zeroes and ones, which can then be represented as a decimal number, or as a hexadecimal number.
The eighth bit, which is one full byte, is traditionally used for checking purposes. The original ASCII standard defines different characters within seven bits – seven digits that indicate either a 0 or a 1. That is the reason why ASCII is also built on this system. To understand how it works, you first need to be familiar with how a calculator functions: in a computer, the computational processes are always based off a binary system, meaning that zeroes and ones determine the processes. UTF-8 is also compatible with ASCII, so it also encodes the first 128 characters.ĪSCII is a standard used to represent characters on electronic devices. As a result, Unicode based character sets like UTF-8 are now widely accepted: Unicode can accommodate more than a million different characters. Changing between the Latin and Arabic alphabets, for example, isn’t practical. There are extended versions that use an eighth bit so that regional language differences can be displayed. To date, the sign standard has only changed a few times to adapt to new requirements. Since computers cannot handle our alphabet – their internal processes are based on the binary system – ASCII needed to be developed.
As far as predecessors go, there is Morse code and coding that is used in telex writing, whereby a standardized code (e.g., a fixed sequence of acoustic signals) is translated into text. Since it is a purely US-American standard, it’s often called US-ASCII.
Codes 129-159 contain the Microsoft? Windows Latin-1 extended characters.The American Standards Association (ASA, now known as ANSI for American National Standards Institute) had already approved the American Standard Code for Information Interchange (ASCII) in 1963 and provided binding specifications for how electronic devices should display characters.
The table below is according to ISO 8859-1, also called ISO Latin-1. There are several different variations of the 8-bit ASCII table. Character 127 represents the command DEL. You will find almost every character on your keyboard. DEC CodeĬodes 32-127 are common for all the different variations of the ASCII table, they are called printable characters, represent letters, digits, punctuation marks, and a few miscellaneous symbols. Below table contains first 32 ASCII characters which are non-printable control codes that can be used to control the peripherals such as printers.