OpenTracker USB User’s Manual
8
8.
Remote Access
Commands can be issued to the tracker remotely via APRS messages. The
originating station’s callsign must appear in the device’s security authorization
list (see
AUTHLIST
command.) Commands are prefixed with ‘
CMD
’, and the
results of the command, if any, will be send back as an APRS message to the
sending station.
For example, ‘
CMD VERSION
’, sent from an APRS client, will cause the target
device to reply with its firmware version.
In response to a
RESET
command, the device will attempt to send one
acknowledgement before resetting. This is intended to prevent message retries
from causing multiple resets, but especially if the channel is busy there is a
possibility that the acknowledgement will not be sent before the reset is
executed. A
RESET
command should be cancelled after a few retries with no
response received to check if the device has indeed been reset.
9.
Safe Mode
Starting with firmware build 56294, the OpenTracker USB includes a 'safe mode'
option to place the device temporarily into its default configuration. The safe
mode entry condition is checked only when the tracker first powers on or resets.
It should always be possible to recover from an invalid configuration using a
cold boot procedure over the serial interface. This procedure, however, can be
problematic with certain hardware setups. Safe mode offers an alternative to a
serial cold boot.
Safe mode is entered by connecting the digital I/O and 1-Wire bus pins (CN4 pins
7 and 2) together. Connect the pins with a short piece of wire or other
conductive item such as a pair of metal tweezers while the tracker powers up.
The tracker will blink its red LED five times to indicate safe mode entry and will
display *SAFE MODE* in the banner.
While in safe mode, the tracker will operate from a saved copy of the default
configuration, with ports A and B set to AUTO at 4800 baud. Changes to the
configuration will affect the normal configuration and not the saved defaults. To