What's the proper technical term for “high asc

Question

What is the technically correct way of referring to "high ascii" or "extended ascii" characters? I don't just mean the range of 128-255, but any character beyond the 0-127 scope.

Often they're called diacritics, accented letters, sometimes casually referred to as "national" or non-English characters, but these names are either imprecise or they cover only a subset of the possible characters.

What correct, precise term that will programmers immediately recognize? And what would be the best English term to use when speaking to a non-technical audience?

Answer 1

A bit sequence that doesn't represent an ASCII character is not definitively a Unicode character.

Depending on the character encoding you're using, it could be either:

• an invalid bit sequence
• a Unicode character
• an ISO-8859-x character
• a Microsoft 1252 character
• a character in some other character encoding
• a bug, binary data, etc

The one definition that would fit all of these situations is:

• Not an ASCII character

To be highly pedantic, even "a non-ASCII character" wouldn't precisely fit all of these situations, because sometimes a bit sequence outside this range may be simply an invalid bit sequence, and not a character at all.

Answer 2

ASCII character codes above 127 are not defined. many differ equipment and software suppliers developed their own character set for the value 128-255. Some chose drawing symbols, sone choose accent characters, other choose other characters.

Unicode is an attempt to make a universal set of character codes which includes the characters used in most languages. This includes not only the traditional western alphabets, but Cyrillic, Arabic, Greek, and even a large set of characters from Chinese, Japanese and Korean, as well as many other language both modern and ancient.

There are several implementations of Unicode. One of the most popular if UTF-8. A major reason for that popularity is that it is backwards compatible with ASCII, character codes 0 to 127 are the same for both ASCII and UTF-8.

That means it is better to say that ASCII is a subset of UTF-8. Characters code 128 and above are not ASCII. They can be UTF-8 (or other Unicode) or they can be a custom implementation by a hardware or software supplier.

Answer 3

If you say "High ASCII", you are by definition in the range 128-255 decimal. ASCII itself is defined as a one-byte (actually 7-bit) character representation; the use of the high bit to allow for non-English characters happened later and gave rise to the Code Pages that defined particular characters represented by particular values. Any multibyte (> 255 decimal value) is not ASCII.

Answer 4

You could coin a term like “trans-ASCII,” “supra-ASCII,” “ultra-ASCII” etc. Actually, “meta-ASCII” would be even nicer since it alludes to the meta bit.

Answer 5

Taken words from an online resource (Cool website though) because I found it useful and appropriate to write and answer.

At first only included capital letters and numbers , but in 1967 was added the lowercase letters and some control characters, forming what is known as US-ASCII, ie the characters 0 through 127. So with this set of only 128 characters was published in 1967 as standard, containing all you need to write in English language.

In 1981, IBM developed an extension of 8-bit ASCII code, called "code page 437", in this version were replaced some obsolete control characters for graphic characters. Also 128 characters were added , with new symbols, signs, graphics and latin letters, all punctuation signs and characters needed to write texts in other languages, ​such as Spanish. In this way was added the ASCII characters ranging from 128 to 255.

IBM includes support for this code page in the hardware of its model 5150, known as "IBM-PC", considered the first personal computer. The operating system of this model, the "MS-DOS" also used this extended ASCII code.

Answer 6

Non-ASCII Unicode characters.