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Interfacing
The following formats are supported for connection of external
devices: GARMIN proprietary Differential GPS (DGPS), NMEA
0180, 0182, 0183 (versions 1.5, 2.0, 2.3, 3.01), ASCII Text Output,
and RTCM SC-104 input (version 2.0).
The following are the Approved Sentences for NMEA 0183,
version 3.01 output: GPRMC, GPGGA, GPGSA, GPGSV, GPGLL,
GPBOD, GPRTE, and GPWPL. The following are the Proprietary
Sentences for NMEA 0183, version 3.01 output: PGRME, PGRMZ,
and PGRMM.
The GPSMAP 378/478 also includes NMEA input with support for
the BWC, DBT, DPT, DSC, DSE, MTW, VHW, VTG, and XTE
sentences.
Garmin’s proprietary communication protocol is available from the
Web site (www.garmin.com).
Removing the GPS Antenna
You can remove the GPS antenna to use an external antenna. After
the antenna is removed, the BNC connector is exposed and ready
for use with an external antenna. For information on connecting an
external antenna to the GPSMAP 378/478, refer to the installation
instructions that came with the antenna.
To remove the GPS antenna:
1. Remove the external power cable from the connector on the
back of the GPSMAP 378/478.
2. Rotate the antenna to approximately a seven o’clock
position. The alignment notches in the casing must line up
with the notches on the antenna.
3. Pull the antenna away from the GPSMAP 378/478 unit.
Removing the GPS Antenna
GPSMAP 378/478 Owner’s Manual 121
APPendIX > InstAllAtIon InforMAtIon