Scott Habgood webster01 at optusnet.com.au
Sun Oct 14 15:35:34 EST 2012

              thanks for getting back to me.

The FMI = Fleet Management Interface, was a function of some Garmin GPS systems (1990's) that allowed the boss of say a courier service to databurst packet info to their employees - employees out in their veh can respond back. It allows the Garmin 350 to display callsign info as a Point Of Interest on the GPS, it needs the special cable (translator) from Argent Data Systems to do this. This also allows you to send and receive messages like you would for texting SMS or as you would on APRS.fi maps. The GPS is NMEA 0138 input/output format & the cable/TNC recognises this.To bring up the "Despatch" menu on the GPS, all you need do is plug in the translator cable & it appears (can reset the GPS back to normal use if required).

The OT3 (TNC) has test functions built into it to adjust your audio level, test tones can be produced to adjust audio, check the TX PTT & some other functions of the TNC, I can get the functions to work fine - but with no audio tones for testing the TX. This should be TX'd over RF & heard by another RXCVR  - I've tried. This is all done from the PC program. I know the GPS and translator cable work fo TXing a msg  as I can send commands to the TNC (OT3) and I get an answer back after it has interrogated it, I can even send a msg to my VX8GR & the RF signal is picked up at VK2RCC-1 & I can see myself on APRS.fi maps.

I plug a USB cable into the OT3 to interrogate/program it.The GPS & radio are still connected when this occurs, although I can and have removed them previously for programming  - no effect. I have adjusted the configuration as suggested from APRS .net website for OT3's & even from the guy that makes these units (Scott Miller in USA).  - NO JOY!

The TNC has several modes, tracker being one of them. I'm using it as "Garmin" on the A port.

You are quite correct - they do work somewhere else, just not for me. I am unsure if it is hardware or configurations. I have been told it is a matter of adjusting the audio level to get the TNC to work correctly. That may be the case but I don't see how if it is already TXing some msg's from the GPS, but NOT RXing it. My understanding is the audio setings are for the TX to allow correct deviation configuaration. I thinkthe problem lies in GPS / cable / TNC. The FT8800R is correctly setup for packet.

I thought somebody out there may have experienced the same  problem, I'm the only APRS user around these parts so bit hard to find help.

Sorry for being long winded - hope this clarifies things.

  ----- Original Message ----- 
  From: Andrew Rich 
  To: Australian APRS Users 
  Sent: Sunday, October 14, 2012 10:48 AM
  Subject: Re: [OZAPRS] HELP WITH GARMIN NUVI 350 & OT3m

  Will try and help


  + I see a radio FT8800R ( Audio device )
  + I see a Garmin NUVI 350 - navigator  ( Digital device )
  + I see a TNC Argent System OT 3 TNC ( Audio / digital device )
  + A cable to connect the Garmin to I assume OT3 TNC 


  + Garmin is not functioning as expected - not displaying POI ( assume input to GARMIN - digital )
  + Garmin is not RX messages or sending from FMI ( GPS )
  + Can't get the Test Tones to work ( I assume you mean TX ) by using a separete RX 


  + Is the FMI ( GPS ) the Garmin ?
  + Does the OT3 do these functions ?
  + What do you mean by "speaker" ?


  + Do you have access to a scope ?
  + Or even a logic probe
  + You need some basic test gear
  + Configs, baud rates, parity.length 
  + How would the test tones test help your situation ? I assume you are plugging in to the OT3 with a PC and removing the Garmin ?
  + Does the OT3 have two different modes ? TNC and Tracker ?

  I assume this all works somewhere else, it is a config or connection issue ?

  - Andrew VK4TEC - 

    ----- Original Message ----- 
    From: Scott Habgood 
    To: ozaprs at aprs.net.au 
    Sent: Sunday, October 14, 2012 9:10 AM
    Subject: [OZAPRS] HELP WITH GARMIN NUVI 350 & OT3m

    Good morning, 
                          I'm after some help with my APRS mobile set up. I've got a FT8800R, Garmin Nuvi 350 & Argent Data System OT 3 TNC. 

    The OT3 is operating the radio correctly. My problem is the garmin 350 is not displaying POI, receiving messages or sending any messages from the FMI (GPS unit). I have the correct Garmin cable from Argent Data Systems. 

     I have tried the configuration program for the Open Tracker 3 & cant get any of the test tones to work (I cant hear them form my speaker or another radio).Can anyone shed some light - I'm getting frustrated with it.


    Dubbo NSW


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