This format can...
read and write waypoints
Support for Destinator™ binary POI files (.dat).
The basic information was found at mozoft.com. GPSBabel can read and write all fields described at this document. Please note that 'house number' isn't supported as a separate field. This field, if available in any source file, will be stored together with 'street' into GSPBabel's internal 'address' field.
Destinator™ by Destinator Technologies is a software for PNDs, Smartphones and PDAs.
gpsbabel -i destinator_poi -f interesting_places.dat -o gpx -F interesting_places.gpx