[aprssig] X-APRS: a new protocol in APRSdroid

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Sat Apr 1 08:11:18 EDT 2017

I glanced through the specification and have a few questions:

1) How are filters handled?  I tapped into the sample feed and that's 
WAY more data than I'd like to have streaming to my mobile phone.

2) How can a client know if a legacy aprs1 packet has been Base-64 
encoded or if it just happens to contain only Base-64 characters? I 
didn't see anything in the specification (end of page) to indicate the 

3) Is there a separate discussion group for this proposal?  Or are we 
supposed to spam the APRS groups with our comments ending up with 
different discussion threads in multiple groups?

And one comment:  VERBOSE!  In the case of paid mobile data plans and 
1200 baud RF channels, more (or even standards-based) is not always better.

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

PS.  Not all of us like adopting 3rd party code over which we have no 
control so making statements like "using one of the many available XMPP 
libraries" doesn't do much for us.

On 4/1/2017 3:32 AM, Georg Lukas wrote:
> Hi all,
> in the past I've often realized that APRS-IS does not work well with
> mobile TCP/IP - latency on 2G or 3G causes delays that skew the position
> reports; interruptions in the data connection are almost impossible to
> detect at application level, and thus cause packet drops, etc.
> On the other hand, with my other project (yaxim, a mobile client for the
> Extensible Messaging and Presence Protocol / XMPP), all of these
> problems have been solved years ago. Now I have come to the conclusion
> that APRS and XMPP have many things in common:
> - They are both network protocols to send real-time GPS and message
>    packets.
> - They are mainly parsed by computers and displayed in a processed form.
> - Both have a vast network of distributed servers to distribute data.
> - For both, there are sophisticated web interfaces available.
> - etc.
> Therefore, I decided to bring together the best of both worlds and
> created X-APRS: a revival of APRS based on the XMPP protocol.
> You can find the protocol specification with color-coded examples here:
> https://aprsdroid.org/xaprs/
> Starting with the upcoming version 1.4, APRSdroid will only support
> X-APRS over TCP/IP and HamNet, and legacy ARPS will be slowly phased
> out.
> However, this should not be a problem, as the new protocol will also be
> supported by aprs2net and aprs.fi (expect separate announcements soon).
> Client and server developers are encouraged to jump in and implement the
> protocol, using one of the many available XMPP libraries.
> You can have a peek at the data stream by issuing one of the following
> commands:
> 	telnet xaprs.aprsdroid.org 20482
> 	telnet 20482
> 73 from Germany,
> Georg DO1GL
> _______________________________________________
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> aprssig at tapr.org
> http://www.tapr.org/mailman/listinfo/aprssig

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