Garmin gpsmap 198c sounder User Manual

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NTERFACING

The following formats are supported for connection of external 

devices:
Garmin proprietary Differential GPS (DGPS), NMEA 0183 

versions 2.3, ASCII Text Output, RTCM SC-104 input (vs. 2.0).
The following are the sentences for NMEA 0183, vs. 2.3 output:
Approved sentences—GPRMC, GPGGA, GPGSA, GPGSV, 

GPGLL, GPBOD, GPRTE, and GPWPL.
Proprietary sentences—PGRME, PGRMZ, and PSLIB. The 

GPSMAP 198C Sounder accepts NMEA input with support for the 

DBT, DPT, MTW, and VHW sentences.  

The GPSMAP 198C Sounder also includes NMEA input with 

support for the WPL sentence and sonar NMEA input with support 

for the DPT (Depth), MTW (Water Temp) and VHW (Water Speed 

& Heading) sentences. If connecting to COM 2 for sonar NMEA 

input, the unit interface must be set to NMEA In/NMEA Out. If 

connecting to COM 1, the unit must be set to NMEA In/NMEA 

Out.
You can download a copy of Garmin’s proprietary communication 

protocol on the Help and Support section of our Web site at  

www.garmin.com. 
Complete information regarding NMEA and RTCM formats is 

available for purchase at www.nmea.org