CP850

Code Page 850, also known as IBM850, is an 8-bit character set used by IBM PC compatibles running DOS to represent Western European text. It extends ASCII by using the upper half of the byte (0x80–0xFF) to encode additional characters while preserving 0x00–0x7F for standard ASCII.

The upper half of CP850 contains accented letters and ligatures common in Western European languages, such as é, è, ä, ö, ç, ñ, and ø, along with various punctuation marks and a small set of box-drawing glyphs. This made it a practical choice for multilingual software and data in the DOS era.

Usage and history: CP850 was introduced to replace CP437 for systems needing broader Western European language support. It was widely used on European PC DOS and MS-DOS installations and remained common in legacy software and data formats for many years. With the rise of Unicode in the late 1990s and beyond, CP850 declined in prominence but remains relevant for reading or converting older files and for environments that emulate DOS behavior.

Compatibility and mapping: CP850 is distinct from Windows ANSI code pages (such as CP1252) and from other DOS code pages. Modern programs typically convert between CP850 and Unicode, using established mappings defined by IBM and implemented in standard encoding libraries. CP850's continued presence is mainly in legacy contexts, software compatibility, and data preservation concerns.