0x1D

0x1D is a hexadecimal numeral representing the decimal value 29. In computing, this value is most commonly encountered as a control code in ASCII and as the corresponding Unicode code point U+001D. In ASCII, 0x1D is known as the Group Separator (GS) character, a non‑printable control code historically used to divide data groups within a text stream or protocol. In Unicode, the code point U+001D is named INFORMATION SEPARATOR THREE, reflecting its historical role as a separator; in practice it is typically treated as a non‑printing character.

Usage and context: 0x1D appears in binary data and various legacy formats as a delimiter or sentinel in certain systems. In modern text processing, it is rarely used as a visible character, and many programming languages treat it as a control code that does not produce a printable glyph. When encoded in UTF-8, the code point U+001D encodes as a single byte 0x1D, since its value lies within the ASCII range.

Technical notes: The 0x prefix denotes hexadecimal notation, a common convention in many programming languages and data specifications. As a byte value, 0x1D may be used directly in code to represent a control character, but its meaning depends on the surrounding protocol, encoding, or data format rather than on the value alone.

See also: ASCII control characters; Unicode control characters; Group Separator; Information Separator Three.