Garmin GPSMAP 12 3 Series Owner's Manual page 205

Receive
Sentence
DPT
DBT
MTW
VHW
WPL
DSC
DSE
HDG
HDM
MWD
MDA
MWV
VDM
You can purchase complete information about National Marine Electronics Association (NMEA) format and
sentences from www.nmea.org.
Appendix
Description
Depth
Depth below transducer
Water temperature
Water speed and heading
Waypoint location
Digital selective calling information
Expanded digital selective calling
Heading, deviation, and variation
Heading, magnetic
Wind direction and speed
Meteorological composite
Wind speed and angle
AIS VHF data-link message
193