[aprssig] aprssig Digest, Vol 94, Issue 11

Tue Apr 10 08:04:45 EDT 2012

Hi, there is any APRS program how works like a messenger? I think is
very important in emergency when I need chat with other station or
other stations easy and fast. What do you think about it?

HK3PQI

Eduardo Gómez L.
Editor conceptual de entretenimiento
Caracol Televisión

El 10/04/2012, a las 7:00 a.m., "aprssig-request at tapr.org"
<aprssig-request at tapr.org> escribió:

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> Today's Topics:
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>   1. Re: APRS message-handling algorithms / libraries (Gary Schelske)
>   2. Re: APRS message-handling algorithms / libraries (Georg Lukas)
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> ----------------------------------------------------------------------
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> Message: 1
> Date: Mon, 9 Apr 2012 23:37:12 -0500
> From: Gary Schelske <gs2042 at yahoo.com>
> Subject: Re: [aprssig] APRS message-handling algorithms / libraries
> To: TAPR APRS Mailing List <aprssig at tapr.org>
> Message-ID: <13A806F3-AAA2-4CA7-90D4-A5590FB4337F at yahoo.com>
> Content-Type: text/plain; charset="us-ascii"
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> Sent from my iPad
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> On Apr 8, 2012, at 12:24 PM, John Goerzen <jgoerzen at complete.org> wrote:
>
>> Hi folks,
>>
>> I am looking to write some APRS software, and I'm hoping to avoid re-inventing the wheel.  I am particularly interested in libraries in any cross-platform language (C, Perl, Python, Java, etc.) that can be used to receive and generate APRS messages.
>>
>> In my research, there are quite a few libraries that receive APRS messages, but I have found none that are helpful with generating them.  This seems to be something with some complexity; such as:
>> Splitting data up into packets of the appropriate size (APRSLink for Winlink appears to somehow detect the type of device in use and generates shorter messages for TH-D7A.  Anyone know how to do this, and what are the appropriate sizes for the D7A, D72A, 710, and VX-8GR?)
>> Processing/generating ACKs, REJs, etc.
>> Proper timing for retransmit of packets that weren't ACKed.
>> None of this is hugely complicated, and the APRS spec is fairly clear on the ACK, REJ, etc. process.  The maximum message sizes appear to be undocumented and I'm hoping someone can help me out there.
>>
>> My project, incidentally, is to build a bidirectional APRS-XMPP bridge.  XMPP is the protocol behind the instant messaging tools such as Jabber and Google Talk, and is available for free on every modern platform.  In the spirit of both amateur radio and the Free Software communities I'm a part of, full source code to this project will be available.  I actually already wrote a much simpler piece of related software, letting someone take a connected AX.25 session and bridge it to XMPP, [1] so I do have some experience under my belt.  This is obviously a more complex project, but XMPP looks like an excellent way to bridge APRS to other systems.  I think it is a better fit than the email gateways out there, and in fact, XMPP already has fields for carrying presence information and location information with presence packets.
>>
>> Are there any particular notes available to those implementing gateways between APRS and non-APRS sources?  I have taken note of what sites such as OpenAPRS or Winlink do to validate people for access, and plan to do something similar here.
>>
>> Thanks,
>>
>> -- John
>> KR0L
>>
>> [1] source code at https://github.com/jgoerzen/ax25xmpp
>>
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> ------------------------------
>
> Message: 2
> Date: Tue, 10 Apr 2012 08:02:52 +0200
> From: Georg Lukas <georg at op-co.de>
> Subject: Re: [aprssig] APRS message-handling algorithms / libraries
> To: TAPR APRS Mailing List <aprssig at tapr.org>
> Message-ID: <20120410060252.GA13519 at ovgu.de>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Gregg,
>
> * Gregg Wonderly <gregg at wonderly.org> [2012-04-09 05:58]:
>> Back in 2001-2003, I worked on a Java APRS application framework
>> called JeAPRS.   The project is out on http://jeaprs.dev.java.net.
>
> I can not speak for John here, but when I started APRSdroid, I was not
> able to find anything even remotely usable from a Java app, so I started
> with my own parser, which was later on replaced by java-aprs-fap [1],
> the Java port of the Perl parser. javAPRSlib is based on the
> java-aprs-fap code, and both John and I try hard to make it usable as a
> library.
>
> It does not include message segmentation and timeout handling. The
> former should be possible to add without too much work if the need
> arises, and the latter should be implemented at application level anyway
> (timeout handling always depends on what kind of I/O interface you use).
>
> As for non-Java solutions, there is of course the excellent Perl
> module maintained by Hessu [2], which is in use on aprs.fi.
>
>
> 73,
>
> Georg DO1GL
>
> [1] http://repo.ham.fi/svn/java-aprs-fap
> [2] http://search.cpan.org/dist/Ham-APRS-FAP/
> --
> APRSdroid - Open Source APRS Client for Android ++ http://aprsdroid.org/m
>     ++ https://market.android.com/details?id=org.aprsdroid.app ++
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