Adding APRS to any wireless APP                            12 Nov 08
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As part of the Universal Amateur Radio text Messaging Initiative, 
our goal is to have applications running on all wireless devices in 
use by hams so that they can communiate with any other ham radio 
operator anytime anywhere by callsign alone.

Please see www.aprs.org/aprs-messaging.html

Since any ham with packet or any of the new APRS integrated radios
can send and receive text messages and email anywhere to anyone 
with a callsign, we want to extend this capability to all devices 
that may be in the hands of a ham at any time.  This is the 
ultimate in terms of emergency response.

It is so simple to add APRS to any device.

1) The device formulates a position packet to show where it is
2) It sends that in periodically into the global APRS-Internet
3) It can send any text-message into the same APRS-Internet port

The APRS-Internet system already knows how to deliver any such text
message to the end user only knowing its callsign alone.  The 
above 3 items are trivial to program and fully integrate that
station into APRS and make the station capable of sending text
messages to any other ham by callsign.

Since any APRS station can send Email text-messages too, then the 
cellphone or other wireless APP is assumed to get his reply messages
via conventional email.

However, it is just as trivial to receive APRS text messages and also
to plot the locations of surrounding users with some simple additional
processes:

4) Monitor the same APRS-IS port for any messages to your CALLSIGN
5) Monitor all APRS traffic within a range of your location and
   either list this, or plot it on a crude map.

Done.

The format for the outgoing (optional) position report is:

   CALLSIGN>APxxxx:!DDMM.mmN/DDDMM.mmW$comment_text...

The format for an outgoing message to W3XYZ would be

   CALLSIGN>APxxxx::W3XYZ....:message_text.....{##

Where the APxxxx identifies the specific APP just for info.
Where the {## is a line number so that lines arrive sequentially

The APRS-Internet port can be any of the multiply-redundant and
cross connected "first.aprs.net" or "second.aprs.net" or "third..."
etc.  Or they can be any of the Tier-2 servers located all over the
world. 

If you want to write a "Universal Amateur Radio Text Messaging app,
please let me help you with any finer details.

Bob, Wb4APR