[aprssig] APRS Message character sets ?

Stephen H. Smith wa8lmf2 at aol.com
Wed Jul 9 21:41:35 EDT 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
> characters.

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
EchoLink Node:      14400    [Think bottom of the 2M band]
Home Page:          http://wa8lmf.com  --OR--   http://wa8lmf.net

NEW!   World Digipeater Map

JavAPRS Filter Port 14580 Guide

"APRS 101"  Explanation of APRS Path Selection & Digipeating

Updated "Rev H" APRS            http://wa8lmf.net/aprs
Symbols Set for UI-View,
UIpoint and APRSplus:

More information about the aprssig mailing list