a.) 437 (DOS) Latin US / CP437

IBM PC or MS-DOS code page (table) with the numerical designation 437, often abbreviated CP437 denoted with the label, but also known as DOS-US and OEM-US or sometimes confusing as OEM font, plus ASCII or extended ASCII. Original character set IBM PC in 1981. The code is based on the replacement of 8 bits. The original ASCII code table is based on a 7-bit code-term substitutes (Table 2.2.1), which is the eighth to be extended to a more 128 characters that are specific to particular localities, regarding the placement of computer equipment markets worldwide. So they created CP850 (Western Europe, France, England, Germany ..), CP852 (Central Europe, Yugoslavia , Poland, Romania ..), CP865 (Nordic countries) and others. Her feature lots of graphic characters that are used in programming for the design of software. They used the original DOS and Windows operating systems.