Each screen character is defined by a code (number). Operating systems and applications need to know these codes to attach meaning to individual characters. A character set provides a code for every character. For your operating system/application to interpret a character correctly, you need to use the correct character set.
Note: Character sets are distinct from fonts. A font defines the visual/appearance properties of a character, not its meaning.
ASCII (American Standard Code for Information Interchange) is a widely adopted 7-bit code specifying the basic alphanumeric character set of the English language. For example, the character capital "A" has the ASCII value of 65, the character lowercase "a" a value of 97.
The ASCII character set contains 96 characters and is commonly used as a standard for protocols and files.
Much of CitectSCADA uses ANSI (American National Standards Institute) character sets. ANSI character sets are language-based, with each different language version of Windows (French, Korean and so on) requiring a specific ANSI character set. Codes 32 to 127 contain standard ASCII characters.
Windows uses Unicode, but still supports ANSI character sets. Several of CitectSCADA's utilities have been created for Unicode, for instance Process Analyst. Unicode accommodates known character sets by having one 16-bit (worldwide) character encoding standard.