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aprsdigi-2.4.4/aprsmon.html
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aprsmon - monitor APRS AX.25 traffic for javAPRS
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<H2>SYNOPSIS</H2><PRE>
<STRONG>aprsmon</STRONG> <STRONG>[-a]</STRONG> <STRONG>[-m]</STRONG> <STRONG>[-r]</STRONG> <STRONG>[-k</STRONG> <STRONG>minutes]</STRONG> <STRONG>[-p</STRONG> <STRONG>port]</STRONG> <STRONG>[-t</STRONG> <STRONG>title]</STRONG>
<STRONG>[-i</STRONG> <STRONG>infofile]</STRONG>
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<H2>DESCRIPTION</H2><PRE>
<STRONG>Aprsmon</STRONG> uses SOCK_PACKET facilities to provide a network
monitor of all AX.25 UI text traffic heard by the system.
It is based on listen(1).
<STRONG>Aprsmon</STRONG> collects (-m) or displays standard AX.25 UI text
frames in a format similar to that output by a standard
TNC in "Monitor ON" mode and is intended to be used with
programs like javAPRS which wish to see a TNC data stream
over a TCP connection. When the <STRONG>aprsmon</STRONG> master has been
running for a while and a new <STRONG>aprsmon</STRONG> slave starts up,
first all saved up reports are sent, then a title line
indicating the beginning of live data is sent, and new
reports are sent as received.
Compressed position and telemetry reports as generated by
the APRS Mic Encoder are translated into the conventional
uncompressed APRS Micro-Interface-Module (MIM) telemtry
format so that these stations are visible in javAPRS.
Reports containing a TheNet X1J4 beacon header are also
edited to strip off the header making these nodes visible
in javAPRS as well.
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<H2>OPTIONS</H2><PRE>
<STRONG>-a</STRONG> Allow for the monitoring of outgoing frames as
well as incoming ones.
<STRONG>-r</STRONG> Choose "raw" mode which allows non-printable
data through.
<STRONG>-p</STRONG> <STRONG>port</STRONG> Monitor only those frames received on a particu-
lar port, by default all AX.25 interfaces are
monitored.
<STRONG>-m</STRONG> "Master" mode. Retain monitored data for the
number of minutes specified with the <STRONG>-k</STRONG> option
in a shared memory segment.
<STRONG>-k</STRONG> <STRONG>minutes</STRONG>
Retain monitored packets going back the given
number of minutes. Default is 30.
<STRONG>-t</STRONG> <STRONG>title</STRONG> Sets the <EM>javAPRS</EM> title string. Default is "Live
data from Linux."
<EM>Infofile</EM> is the path to the file that the
aprsmon master writes the shared memory segment
and semaphore id's into. Default is
"/var/ax25/aprsmon.info."
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<H2>javAPRS CONFIGURATION</H2><PRE>
Set up one <EM>aprsmon</EM> master running on your system to col-
lect historical data going back a while. You will proba-
bly want to set up an /etc/rc.d/init.d script for this.
aprsmon -a -m&
Add an entry into /etc/services with the port number you
want javAPRS to connect on. For example:
aprs 14439/tcp # APRS monitor on 144.39
Add an entry into /etc/inetd.conf for this service:
aprs stream tcp nowait root /usr/sbin/aprsmon aprsmon -a
To test, simply "telnet localhost aprs". To use with
javAPRS, set, for example,
<PARAM name = "dataFile1" value = "netc:14439:localhost">
in your HTML file as described in the <STRONG>javAPRS</STRONG> documenta-
tion, and then use <STRONG>appletviewer</STRONG> to run javAPRS:
appletviewer mydemo.html
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<H2>Mic-E to MIM Translation</H2><PRE>
The Mic-E reduces the duration of packet noise on a voice
frequency by encoding its data in a compressed form, some
of which is binary. Some APRS-decoding software, notably
javAPRS, is unable to deal with this data. To solve this
problem <STRONG>aprsmon</STRONG> expands the Mic-E packet into one or two
MIM packets as follows:
@<STRONG>ddhhmm</STRONG>z<STRONG>DDMM.hhN/DDDMM.hhW$cse/spd/E</STRONG>>mon/M<STRONG>m</STRONG>/<STRONG>status</STRONG>
T#MIC,<STRONG>aaabbbcccdddeeefffComments</STRONG>
<STRONG>ddhhmm</STRONG> is the UTC day and time the packet was received
by the host running <STRONG>aprsmon.</STRONG>
<STRONG>DDMM.hhN</STRONG> is the latitude.
<STRONG>/</STRONG> is the symbol table selection (/ or \).
<STRONG>DDDMM.hhW</STRONG> is the longitude.
<STRONG>$</STRONG> is the symbol.
<STRONG>E</STRONG> is the type of Mic-Encoder:
E - TAPR Mic-Encoder
T - Kenwood TH-D7
<STRONG>m</STRONG> is the status message number, and
<STRONG>status</STRONG> is the status message number expanded as fol-
lows:
0 - Off duty..
1 - Enroute...
2 - In Service
3 - Returning.
4 - Committed.
5 - Special...
6 - PRIORITY..
7 - EMERGENCY.
<STRONG>aaa,bbb,ccc,ddd,eee,fff</STRONG>
are the values of the telemetry channels.
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<H2>FILES</H2><PRE>
<STRONG>/etc/ax25/axports</STRONG> <STRONG>/var/ax25/aprsmon.info</STRONG>
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<H2>SEE ALSO</H2><PRE>
<STRONG>call</STRONG>(1), <STRONG>listen</STRONG>(1), <STRONG>beacon</STRONG>(1), <STRONG>ax25</STRONG>(4), <STRONG>axattach</STRONG>(8),
<STRONG>http://www.bridge.net/~sdimse/javAPRS.html,</STRONG>
<STRONG>http://www.tapr.org,</STRONG> <STRONG>http://www.aprs.net,</STRONG> <STRONG>MIC-</STRONG>
<STRONG>E.TXT,</STRONG>TELEMTRY.TXT,<STRONG>PROTOCOL.TXT</STRONG>
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<H2>AUTHOR</H2><PRE>
Alan Crosswell, n2ygk@weca.org
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