http://www.unicode.org/faq//utf_bom.html
Q: Is there a standard method to package a Unicode character so it fits an 8 -Bit ASCII stream?
A: There are three or four options for making Unicode fit into an 8-bit format.
a) Use UTF-8. This preserves ASCII, but not Latin-1, because the characters >127 are different from Latin-1. UTF-8 uses the bytes in the ASCII only for ASCII characters. Therefore, it works well in any environment where ASCII characters have a significance as syntax characters, e.g. file name syntaxes, markup languages, etc., but where the all other characters may use arbitrary bytes.
Example: “Latin Small Letter s with Acute” (015B) would be encoded as two bytes: C5 9B.
b) Use Java or C style escapes, of the form \uXXXXX or \xXXXXX. This format is not standard for text files, but well defined in the framework of the languages in question, primarily for source files.
Example: The Polish word “wyjście” with character “Latin Small Letter s with Acute” (015B) in the middle (ś is one character) would look like: “wyj\u015Bcie".
c) Use the XXXX; or DDDDD; numeric character escapes as in HTML or XML. Again, these are not standard for plain text files, but well defined within the framework of these markup languages.
Example: “wyjście” would look like “wyjście"
d) Use SCSU. This format compresses Unicode into 8-bit format, preserving most of ASCII, but using some of the control codes as commands for the decoder. However, while ASCII text will look like ASCII text after being encoded in SCSU, other characters may occasionally be encoded with the same byte values, making SCSU unsuitable for 8-bit channels that blindly interpret any of the bytes as ASCII characters.
Example: “<SC2> wyjÛcie” where <SC2> indicates the byte 0x12 and “Û” corresponds to byte 0xDB. [AF] & [KW]
