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       aprsmon - monitor APRS AX.25 traffic for javAPRS


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


       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.


       -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

       -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

       -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/"


       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

       <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:


       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.

                 are the values of the telemetry channels.


       /etc/ax25/axports /var/ax25/


       call(1),      listen(1),      beacon(1),      ax25(4),     axattach(8),,,, MIC-E.TXT,TELEMTRY.TXT,PROTOCOL.TXT


       Alan Crosswell,