10.1 How do I make Emacs display 8-bit characters?

See Single-byte Character Set Support in The GNU Emacs Manual. On a Unix, when Emacs runs on a text-only terminal display or is invoked with ‘emacs -nw’, you typically need to use set-terminal-coding-system to tell Emacs what the terminal can display, even after setting the language environment; otherwise non-ASCII characters will display as ‘?’. On other operating systems, such as MS-DOS and MS-Windows, Emacs queries the OS about the character set supported by the display, and sets up the required terminal coding system automatically.