APRSMON(8)						     Linux Programmer's Manual							APRSMON(8)

NAME

       aprsmon - monitor APRS AX.25 traffic for javAPRS

SYNOPSIS

       aprsmon [-a] [-m] [-r] [-k minutes] [-p port] [-t title] [-i infofile]

DESCRIPTION

       Aprsmon	uses  SOCK_PACKET  facilities  to provide a network monitor of all AX.25 UI text traffic heard by the system.  It is based on lis-
       ten(1).

       Aprsmon 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 aprsmon master
       has been running for a while and a new aprsmon 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.

OPTIONS

       -a	 Allow for the monitoring of outgoing frames as well as incoming ones.

       -r	 Choose "raw" mode which allows non-printable data through.

       -p port	 Monitor only those frames received on a particular port, by default all AX.25 interfaces are monitored.

       -m	 "Master" mode.  Retain monitored data for the number of minutes specified with the -k option in a shared memory segment.

       -k minutes
		 Retain monitored packets going back the given number of minutes.  Default is 30.

       -t title  Sets the javAPRS title string.  Default is "Live data from Linux."

       -i infofile
		 Infofile  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."

javAPRS CONFIGURATION
       Set up one aprsmon master running on your system to collect historical data going back a while.	You  will  probably  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 javAPRS documentation, and then use appletviewer to run javAPRS:
       appletviewer mydemo.html

Mic-E to MIM Translation
       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 aprsmon  expands	the  Mic-E  packet
       into one or two MIM packets as follows:

       @ddhhmmzDDMM.hhN/DDDMM.hhW$cse/spd/E>mon/Mm/status
       T#MIC,aaabbbcccdddeeefffComments

       ddhhmm	 is the UTC day and time the packet was received by the host running aprsmon.

       DDMM.hhN  is the latitude.

       /	 is the symbol table selection (/ or ).

       DDDMM.hhW is the longitude.

       $	 is the symbol.

       cse,spd	 are course and speed.

       E	 is the type of Mic-Encoder:

		 E - TAPR Mic-Encoder
		 T - Kenwood TH-D7

       m	 is the status message number, and

       status	 is the status message number expanded as follows:

		 0 -  Off duty..
		 1 -  Enroute...
		 2 -  In Service
		 3 -  Returning.
		 4 -  Committed.
		 5 -  Special...
		 6 -  PRIORITY..
		 7 -  EMERGENCY.

       aaa,bbb,ccc,ddd,eee,fff
		 are the values of the telemetry channels.

FILES

       /etc/ax25/axports /var/ax25/aprsmon.info

SEE ALSO

       call(1),  listen(1), beacon(1), ax25(4), axattach(8), http://www.bridge.net/~sdimse/javAPRS.html, http://www.tapr.org, http://www.aprs.net,
       MIC-E.TXT,TELEMTRY.TXT,PROTOCOL.TXT

AUTHOR

       Alan Crosswell, n2ygk@weca.org

Linux								  9 February 1999							APRSMON(8)