Character strings are based on an understanding of what is meant by a character. The standard may be specified as ASCII (7 bit, ANSI X3.4), Extended ASCII (8 bit, as commonly used on microcomputers), Unicode, or an ISO designation. A version number may be given for the standard. If the interpretation of the characters involves some private understanding (with specialized software) then private is set to true; normally this is not the case and the default applies. A code or sequence may also be given.