ANSI
American National Standards Institute (ANSI) is "An organization of American industry groups that work with other nations to develop standards in facilitating telecommunications, character encoding and international trade." (MultiLingual)
ANSI was connected with a proposal for an 8-bit character set, and the abbreviation has been used to describe the 8-bit used by Microsoft Windows.
References
AlanWood.net, "ANSI character set and equivalent Unicode and HTML characters," http://www.alanwood.net/demos/ansi.html
MultiLingual. 2007. "Glossary." 2007 Resource Directory. http://www.multilingual.com/resourceDirectory/
Wikipedia, "ANSI," http://en.wikipedia.org/wiki/ANSI
______, "Windows code page," http://en.wikipedia.org/wiki/Windows_code_page