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           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 listen(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 particu-
                     lar  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."

                     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 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 javAPRS documenta-
           tion, 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.

           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  fol-
                     lows:

                     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