Character Encoding, BOM, Endianness

In order to encode foreign language symbols and other graphic characters, the Unicode character set and encoding schemes were developed.   The most common encoding scheme is UTF-8.   UTF-8 is backward compatible with the more simple ASCII standard.   The Byte Order Mark (BOM) is a Unicode character U+FEFF that appears at the start of a text stream.  

Endianness

Endianness refers to the sequential order in which bytes are arranged into larger numerical values when stored in memory or when transmitted over digital links.   The format may vary devpending on whether bits or bytes are ordered from the most significant bit (big end; e.g. big-endian) or the least significiant end (little end, e.g. little-endian).   See Wikipedia.   Network Byte Order refers to how bytes are arranged when sending data over a network (big-endian).   System or Host Byte Order refers to how bytes are arranged when stored in memory on the host system (Windows OS is Little Endian).  

Understanding Big and Little Endian Byte Order

Note that if you transfer data from one computer to the next and you don't have the same endianness, then the data will not be represented properly by the recipient.   A single byte will be represented properly on any two computers, but a sequence can be misunderstood.