This format can...
read tracks
This format has the following options: erase .
Serial download protocol for the GlobalSat DG-100™ GPS data logger. Although untested it is expected that this will also support the BT-335.
While the DG-100 has a button to record waypoints, they seem to be indistinguishable from trackpoints. Therefore, all points will be presented as trackpoints, disregarding whether they were recorded automatically or manually.
Example 3.8. Command showing DG-100 download and erase on Linux
gpsbabel -t -i dg-100,erase -o gpx /dev/ttyUSB0 outputfile.gpx
The DG-100 provides a physical USB interface to the host computer, but internally it uses a Prolific PL-2303 chip to do this. So you must have drivers installed on your computer to recognize the PL-2303 and provide that data as a serial port to software like GPSBabel. Such software comes with the unit for Windows. Prolific provides software for Mac OS/X, but unfortunately their driver has a defect which makes it unusable with GPSBabel.