ISO 2955

From: Dreiheller, Albrecht <>
Date: Fri, 5 Jul 2013 14:01:16 +0000

A topic that is different but related to the current discussion "writing in an alphabet with fewer letters: letter replacements"
is the question about writing units with limited character sets.
This is not a somehow academical question but a real existing problem in some situations.

You might remember there was a standard named
ISO 2955-1983 "Information processing -- Representaion of SI and other units in systems with limited character sets".
It has given some rules for writing "deg" for "°", "u" for "µ", "m2" for "m²", and so on.

However it was withdrawn in 2001.
Does anybody know whether there is a successor standard?
If not, does someone know the reason?
DIN 66030 gives a solution for German, are there similar standards for other countries,
especially Japan and China?

Let me briefly outline the context of the question:

Even if ISO 2955 was designed with a focus on systems using ISO 646 (ASCII) as character set,
there are certain issues even in Unicode based systems, especially in Japanese and Chinese context.

Such a context can briefly described as follows:
- Multi language user interface (language switching is possible)
- Only one font per language, plain text only (no font linking, no font fallback, no formatted text)
- East Asian languages use standard third party fonts, like TrueType fonts.
Any kind of embedded devices are good examples.

The simple and often followed rule for East Asian fonts is covering a well-known language-specific
encoding standard, like GB2312 or GBK for Simplified Chinese, Shift-JIS for Japanese,
EUC-KR or UHC for Korean and BIG5 for Traditional Chinese.
Since these standards contain several alphabets like Cyrillic, Latin, Greek, Bopomofo, Kana, and so on,
it is the easiest way for font manufacturers to use the encoding standard as a guideline for the
character set coverage even for fonts designed for Unicode based systems.

Now you buy and install a standard font and your Japanese or Chinese user interface looks beautiful
on the target system. All are happy.
However, this is true only until you have texts with units like km·m/s² or µA/mm².
The translation was done on a Unicode and SI basis, but the font covers only Shift-JIS, GBK,
or BIG5, respectively.
Thus U+00B2 Superscript Two, U+00B3 Superscript Three and U+00B5 Micro Sign are missing in the font
and cannot be displayed. Fonts without these limitations are not easy to obtain.

Thanks in advance for any answer.

Received on Fri Jul 05 2013 - 09:04:31 CDT

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