So first, it looks like the 720 has a NMEA output mode with options. You're going to want 9600 baud, and then likely either the EXTENDED sentence type or CUSTOM with the following sentences selected:
GPRMB - This sentence is needed always. It contains core position, speed, and satellite data.
GPRMC - This sentence is needed always. It contains basic navigational data, including information about origin/destination waypoints and course deviation
GPGGA - Only needed if you want GPS altitude
GPBOD or GPAPB - One of the two sentences must be present, but you don't need both. Contains course direction information. If neither are present, the OBS will always indicate 360.