Windows OEM character set

Windows code pages are sets of characters or code pages (known as character encodings in other operating systems) used in Microsoft Windows from the 1980s and 1990s. Windows code pages were gradually superseded when Unicode was implemented in Windows, although they are still supported both within Windows and other platforms.

There are two groups of code pages in Windows systems: OEM and ANSI code pages. Code pages in both of these groups are extended ASCII code pages.

ANSI code pages (officially called "Windows code pages" after Microsoft accepted the former term being a misnomer) are used for native non-Unicode (say, byte oriented) applications using a graphical user interface on Windows systems. ANSI Windows code pages, and especially the code page 1252, were called that way since they were purportedly based on drafts submitted or intended for ANSI. However, ANSI and ISO have not standardized any of these code pages. Instead they are either supersets of the standard sets such as those of ISO 8859 and the various national standards (like Windows-1252 vs. ISO-8859-1), major modifications of these (making them incompatible to various degrees, like Windows-1250 vs. ISO-8859-2) or having no parallel encoding (like Windows-1257 vs. ISO-8859-4; ISO-8859-13 was introduced much later). About twelve of the typography and business characters from CP1252 at code points 0x80–0x9F (in ISO 8859 occupied by C1 control codes, which are useless in Windows) are present in many other ANSI/Windows code pages at the same codes. These code pages are labelled by Internet Assigned Numbers Authority (IANA) as "Windows-number".

...
Wikipedia