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[aprssig] Please,standardize UTF-8 for APRS

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Fri Dec 18 12:15:30 UTC 2009


I would only add "Path element" to the list that needs 7 bit printable 
ASCII characters.  Some readers may not realize that the path is 
actually composed of callsigns and hence governed by the same restriction.

Also, possibly to avoid the discussion of the printabiltiy of spaces, 
CRLF, punctuation, and delete (127), I'd put the actual valid character 
value range as a parenthetical.

Lynn (D) - KJ4ERJ

Heikki Hannikainen wrote:
> On Thu, 17 Dec 2009, Robert Bruninga wrote:
>
>> To clarify things, I have now created a UTF-8 discussion
>> document that summarizes any issues with UTF-8 and suggests
>> bounds on where it can be used.  I welcome any suggestions or
>> additions to this document to make sure we are all working from
>> the same sheet.  It is the first link listed on:
>> http://aprs.org/aprs12.html
>
> I think you're making it too complicated on that page, for the casual 
> developer, and mixing a lot of terminology. UTF-8 and ASCII are 
> exactly THE SAME for values 0 to 127.
>
> Bytes in the ASCII range of 0–127 represent themselves in UTF, thereby 
> providing backward compatibility.
>
> The whole APRS packet, and the mic-e packet, can be transmitted in 
> UTF-8 encoded format, as the UTF-8 encoded version of the APRS/mic-e 
> protocol data is EXACTLY equal to ASCII. So most of the text on that 
> page is actually rather unnecessary!
>
> I think the required specification boils down to:
>
> -------------------- cut here ------------------
>
> - Using UTF-8 is recommended for all free-form message data:
>     - APRS messaging data
>     - Comment field in compressed and uncompressed packets
>     - Mic-E Status Text Field
>     - Status messages
>     - Bulleting message content
>     - Beacon text
>
> - Using 7-bit printable ASCII characters is mandatory for:
>     - All callsigns
>     - Bulletin / message destinations
>     - Object and item names
>
> The whole APRS packet can be encoded as UTF-8, but character values 
> above 127 must not be used in callsign fields which have strict 
> requirements for length (in bytes) in the encoded form.
>
> -------------------- cut here ------------------
>
> Could you please replace the utf-8.txt contents with that?
>
> Also, it is not necessary to rant about not using UTF-8 in 
> international communications. I think it's rather obvious that when 
> writing to you I should write in English. Which uses characters under 
> the < 127 values, which are EQUAL in UTF-8 and ASCII - it will just 
> work even if I am transmitting in UTF-8 and you are expecting ASCII. 
> So that's covered automatically.
>
>   - Hessu
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