ASCII is a seven-bit code defining 128 values for control functions and characters, including Latin letters, decimal digits and punctuation. Uppercase A has value 65, hexadecimal 41. When stored in an eight-bit byte with the high bit zero, the remaining seven bits carry the ASCII value. RFC20 documents this convention for network interchange.[ref]
The first 128 Unicode code points preserve these assignments, and UTF-8 represents them by the same single-byte values. This compatibility does not make arbitrary eight-bit text ASCII: values 128–255 belong to some other encoding or byte protocol. Nor does the code assign a particular glyph shape or font. Separating a character code from its rendering makes text transport and typography distinct operations.
