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Old November 4th, 2019   #1
FishAI
Junior Member
 
Join Date: Jul 2019
Posts: 3
Post ISO/IEC 646 text encoding

Hello,
I am developing a software tool which can use the RDM protocol and I have a few questions regarding the mentioned ISO/IEC 646 standard when it comes to handling text transmitted via RDM.

At first, ISO/IEC 646 is meant to be a 7 bit standard, but from the fixtures I've seen, they all encode their labels in 1 byte per character.
So am I assuming correctly that most significant bit is always padded with a 0 to comply with the byte pattern?

Second, ISO/IEC 646 defines code points which can be replaced by a local character set, for example 0x23 or 0x5B. What is the correct character set to use when it comes to displaying the text? There are a few options:
  1. Displaying the american character set, where 0x23 is the symbol # and 0x5B is the symbol [
  2. Displaying the character set which corresponds to the current language setting in the fixture (via GET:LANGUAGE, PID 0x00B0)
  3. Displaying the character set which is currently used on the machine running the software, but that could produce inaccurate results

Finally, ISO/IEC 646 defines symbols which are not printable characters, e.g. 0x7F (DEL) or 0x0B (VT). How would a software handle the display of said characters, do you have any advice?

At the time I am very confused by the information E1-20 has given me. Did I miss something?
Best regards,
Robert
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