ASCII 127 — DEL

Delete (DEL) is unique in the ASCII table: it is the only control character outside the 0–31 range, encoded as 127 (binary 1111111, all bits set). On paper tape systems, punching all holes in a position meant 'delete this character,' which is why DEL was assigned the all-ones binary pattern. In modern systems, the Delete key may send either DEL (127) or a multi-byte escape sequence depending on terminal configuration. The longstanding confusion between Backspace (8) and Delete (127) continues to require careful terminal setup.

Control characters were defined in the original 1963 ASCII standard to manage telecommunications equipment and terminal devices. Unlike printable characters representing visible symbols, control codes perform actions: initiating transmissions, acknowledging received data, triggering device alerts, and structuring information hierarchically. Of ASCII's 128 code points, 33 are designated as control characters (codes 0–31 plus 127), reflecting the standard's deep roots in telegraphy and serial communication systems. While most control codes have fallen out of daily use, several remain essential to modern computing workflows.

In the ASCII encoding table, Delete is assigned code point 127 in decimal (0x7F hexadecimal, 177 octal, 01111111 binary). The 7-bit ASCII standard, first published in 1963 by the American Standards Association, defines exactly 128 characters that remain the foundation of text encoding systems worldwide. UTF-8, the dominant encoding on the modern web, is fully backward compatible with ASCII — every ASCII character is encoded as the identical single byte in UTF-8, guaranteeing that Delete works reliably across all operating systems, programming languages, and internet protocols.