Encoding on the Internet
To increase the number of characters encoded, vendors doubled the range of ASCII to 256 (28) characters. This became known as "8-bit encoding". The usual structure is:
Crucially, each combination of an a letter plus a different accent forms a separate character or code point. For instance, á, â, à, Á, Â, and À are assigned six different numbers in 8-bit encoding.
Unfortunately, not all vendors used the same 8-bit encoding. The biggest difference was that older Windows computers use Windows-1252 while pre-OS X Macintosh uses MacRoman encoding. As a result not all characters are assigned to the same points, plus not all the same characters can be found in both encodings.
For instance, in the chart below character #128 is € (euro) in Windows 1252, but Ä (A-umlaut) in Mac Roman. Similarly the ¥ (yen) character is #165 in Windows-1252, but #180 in MacRoman.
NOTE: Today both Windows and OS X use Unicode, but differences persist due to issues of compatibility with older documents and software. The older the software, the more likely compatibility problems will occur.
NOTE: The chart above was generated with the Excel function char(#) in both Mac and Windows. Not all code points have been checked for accuracy.
Additional Reference charts are available from Kosta Kostis.
NOTE: Some charts may list the decimal number (base-10) as well the hexadecimal (base-16) number and octal (base-8) number. In most cases, you would refer to the decimal number.
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