A converter from (almost) code page 437 to unicode and back. (https://en.wikipedia.org/wiki/Code_page_437)
Technically, it converts bytes to unicode characters matching a character set the same as code page 437, except the characters for byte 0 and byte 255 are replaced with distinct printable characters, so that every character appears differently.
This is the character set used:
ₒ☺☻♥♦♣♠•◘○◙♂♀♪♫☼►◄↕‼¶§▬↨↑↓→←∟↔▲▼
!"#$%&'()*+,-./0123456789:;<=>?
@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_
`abcdefghijklmnopqrstuvwxyz{|}~⌂
ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ¢£¥₧ƒ
áíóúñѪº¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐
└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀
αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ȳ
The output is encoded in UTF-8.
I use this character-set to inspect binary files. It's similar to viewing files in MS-DOS Edit in binary mode.
It can also convert text composed of these unicode characters back into byte data.