Re: Hexadecimal in many scripts (ISO 14755)

From: Sandra O'donnell USG (
Date: Tue Jun 08 1999 - 14:54:39 EDT

Throughout this voluminous thread, I've seen several people ask whether
anyone has a keyboard that does NOT include the Latin letters A-Z and
a-z, or the digits 0-9. So far I haven't seen an answer. It seems that
information is needed before worrying much about determining the first
six "letters" in every alphabet.

Since part of this thread points to international standards, I'll
point out that ISO/IEC 9945-2:1992 (otherwise known as POSIX.2)
requires that conforming implementations must support what it calls
the "Portable Character Set" (PCS). If you think of ASCII, you pretty
much have the PCS, although the PCS is missing a few ASCII controls.

Elsewhere in ISO 9945, it defines the class digit: "...Only the
digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 shall be specified..."
The class xdigit (hexadecimal digit) is defined as containing the
characters in the digit class plus a set of six other characters.
Although the definition leaves the door open for using characters
other than A-F and a-f for the other hex digits, it also says: "The
digits 0 through 9, the uppercase letters A through F, and the lowercase
letters a through f...are automatically included in this class."

Now, obviously, not everyone supports POSIX.2, but a goodly portion
of the computer world supports something like it. Windows is built
on top of DOS, which requires the ASCII characters. URLs and the Web
must at a minimum have the ASCII characters. Do we know of an existing
or likely need for a system to be able to enter Unicode in hex without
having the usual hex digits available?

                -- Sandra
Sandra Martin O'Donnell
Compaq Computer Corporation

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