For Windows users, there are two code pages in use. Applications using the Windows graphical user interface use the Windows code page. Windows code pages are compatible with ISO character sets, and also with ANSI character sets. They are often referred to as ANSI code pages.
Character-mode applications (those using a command prompt window) in Windows use code pages that were used in DOS. These are called OEM code pages (Original Equipment Manufacturer) for historical reasons.
SAP Sybase IQ supports collations based on both OEM and ANSI code pages. The OEM collations are provided for compatibility, but they should not be used for new databases.