User`s manual

Tracker3 User’s Manual 20
Also, should a valid password be sent without being received by the target
device, an eavesdropper would know the next valid password. If you are unsure
of being able to reach the target device, send an unauthenticated message or
query first and make sure you get a reply.
17. Garmin Fleet Management Interface
Some Garmin navigation systems provide a Fleet Management Interface (FMI)
that can be used with the Tracker3 with the proper cable. See
http://wiki.argentdata.com for current compatibility information and cable
requirements.
To use the FMI features, set one of the Tracker3’s serial ports to GARMIN mode
and connect the FMI cable. The Tracker3 will automatically place the navigation
system in fleet management mode, which adds a ‘Dispatch’ menu item and may
change the layout of other menus. This mode change can only be reversed by
erasing all user data on the navigation system
Incoming APRS messages will display a message icon on the navigation system’s
screen and will be stored in the inbox. Outgoing messages can be addressed to a
specific station by starting the message with a dash (‘-‘) and the destination
callsign, followed by a space and the message text. If no station is specified, the
message will be sent to the sender of the last message received. This allows
conversations to be carried on without having to constantly re-enter callsigns.
To send a configuration command to the Tracker3, start a message with ‘--’. For
example, ‘-- VERSION ’ will cause the Tracker3 to respond with a message stating
its firmware version.