MSC08-A Character Encoding - Use Subset of ASCII for Safety

The character encoding defined by the ASCII standard is the following: code values are assigned to characters consecutively in the order in which the characters are listed as the table below: starting from 32 (assigned to space) and ending up with 126 (assigned to the tilde character ~). Positions 0 through 31 and 127 are reserved for control codes.

There are several national variants of ASCII. Therefore, the original ASCII is often referred as US-ASCII. The international standar ISO 646 defines a character set similar to US-ASCII, but with code positions corresponding to US-ASCII characters @[]{|}
as "national use positions". It also gives some liberties with characters #$^`~. In ISO 646, several "national variants of ASCII" have been defined, assigning different letters and symbols to the "national use" positions. Thus, the characters that appear in those positions - including those in US-ASCII are somewhat "unsafe" in international data transfer.

Thus, due to the "national variants" discussed above, some characters are less "safe" than others, for example, they might be transferred or interpreted incorrectly.

In Addition to the letters of the English alphabet ("A" to "Z" and "a" to "z"), the digits ("0" to "9") and the space , only the following characters can be regarded as really "safe" in data transmission:

 ! " % & ' ( ) * + , - . / : ; < = > ?

When naming files, variables, data files etc., it is often best to use only the characters listed above.

Comments

The way to resolve this issue is to use the corresponding codes strictly for US-ASCII meanings; national characters are handled otherwise, giving them their own, unique and universal code positions in character codes larger than ASCII. But certain old softwares and devices may still reflect various "national variants of ASCII".