PETSCII

PETSCII (sometimes incorrectly called PET ASCII or CBM ASCII) is an extension of ASCII used on Commodore computers, including the PET, VIC-20, 64, and 128 (but not the Amiga line). It had two different modes, switchable by keyboard or program control, one containing only uppercase letters (along with numbers, punctuation, and many graphic characters) and the other ("text mode") containing both lower and upper case (but putting the lowercase letters where standard ASCII and even the other PETSCII mode have uppercase, and the uppercase letters in a different spot not corresponding to any sort of letters in standard ASCII... but also repeated in the normal spot for lowercase letters, for increased confusion).

PETSCII was based on the obsolete 1963 version of ASCII (even though the 1967 version was released long before PETSCII was devised), so some of its character differences from standard ASCII are attributable to this, but many others are Commodore-specific quirks, including the use of many characters in the set for various line-drawing and other graphical characters, as well as specialized control codes (in both the C0 and C1 ranges) to do such things as change the color of text.

References

• PETSCII (Wikipedia)
• PETSCII to Unicode map: unshifted, shifted