[aprssig] APRS Message character sets ?
Stephen H. Smith
wa8lmf2 at aol.com
Wed Jul 9 20:41:35 CDT 2008
Matti Aarnio wrote:
> I am asking the aprssig to form a consensus of what shall be the canonic
> message character-set and encoding beyond US-ASCII ?
> he APRS specification 1.0.1 defines that used character set is ASCII in
> many places where it defines charactersets at all.
> This is quite understandable in view of TNC2 interfaced systems with
> 7E1 type communication channel -- which is unable to pass thru any extended
1) TNC2-type systems are normally initialized to 8-N-1 (not the
default 7-E-1) for APRS with the TNC commands
(or equivalent for other TNCs) so that they WILL be transparent to 8-bit
characters. This is required so that any arbitrary character values
created by Mic-E encoding will pass. In fact I have modified the TNC2
firmware Ver 1.1.9 to DEFAULT to 8-N-1 bit transparent mode so no init
is even required.
2) Since the APRS network infrastructure is heavily based on legacy
1980s-1990s packet hardware that doesn't support 16-bit/character
encoding (i.e. UniCode), I wouldn't hold my breath for 16-bit support
any time soon. Not to mention that the most widely used APRS
application (UI-View) is now frozen in time and unchangeable.
Stephen H. Smith wa8lmf (at) aol.com
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