OpenTracker USB User’s Manual
6
Mac
OS X
should assign a device name starting with /dev/cu.usbmodem.
Other modern operating systems should be able to use the OpenTracker USB as a
generic CDC ACM serial device. Its VID is 0x134A and PID is 0x9000.
6.
Position Modes
Before getting started, it’s important to understand that the tracker ordinarily
will
not
make automatic transmissions (including position, status, weather, and
telemetry packets) unless it knows where it is.
The device knows where it is when it receives a valid fix from a GPS receiver, or
when it’s programmed by the user with a fixed position. It can be configured to
transmit without a valid fix; if no fix has been received since power-up, only
status and telemetry packets will be sent. If the last valid GPS fix is more than 30
seconds old, a ‘NO FIX’ warning is added to each position packet.
If the
AUTOSAVE
option is enabled, as soon as the last valid fix is 30 seconds old,
that position is saved and the device enters fixed position mode. As soon as
another valid fix is received, it switches back to GPS mode. This is useful for
portable weather stations that will have a GPS receiver connected only briefly
during deployment.
7.
Port Modes
The OpenTracker USB has two serial ports that share the same physical
connector. A ‘Y’ adapter is available to separate the ports if needed. Both ports
can operate in multiple modes:
AUTO
– In this mode, the device will automatically detect NMEA GPS data, Peet
Bros weather data, or (for port A only) command console input. Note that while
both ports can be configured in AUTO mode, only one should be used for a
given function at any time. For example, port A can accept NMEA data while
port B accepts weather data, but providing NMEA data to both ports
simultaneously will cause unpredictable operation.
If the USB port is not in KISS mode, the command console will only be present
on the USB port while it’s connected. When the USB port is disconnected, the
console will default back to port A.