What Does American Standard for Information Interchange (ASCII) Mean?
American Standard for Information Interchange (ASCII) is a method of encoding characters that is based on the order of alphabetic characters in the English language.
ASCII integer representations have printable and nonprintable subsets. Printable characters are normal characters, and nonprintable characters are characters used to represent keyboard keys, e.g., backspace, delete, and return.
Techopedia Explains American Standard for Information Interchange (ASCII)
Technically, ASCII is 7-bit representing only 128 characters (0-127). The range 0-31 are control characters, with 32-127 representing alphabetical characters from A to Z, numerals from 0 to 9 and punctuation marks (though not in that order). ASCII only may be used to encode U.S. English.
Some people confuse codes above 128-255 to be ASCII, but technically speaking, they are not. As computers evolved, it became common to use an 8-bit byte. This last character allowed for an extra 128 characters, which is known as extended ASCII. Different systems implement extended ASCII differently, so there are compatibility issues that aren't encountered in the first 128 characters.