This is a GlobalSat DG-100
It’s an amazing piece of Kit, but the software that comes with it is absolutely rubbish.
You can download all of the routes (and delete them from the unit) in one simple command with gpsbabel.
gpsbabel -t -i dg-100,erase -o gpx /dev/ttyUSB0 outputfile2.gpx
You’ll still need to set up the times/distance for recording for the switch positions A,B & C. I have mine set to 1,5 and 10 seconds. Easiest way to set these up is on a windows machine with DG Manager.