InterfacingThe following formats are supported for connection of externaldevices: GARMIN proprietary Differential GPS (DGPS), NMEA0180, 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 ProprietarySentences for NMEA 0183, version 3.01 output: PGRME, PGRMZ,and PGRMM.The GPSMAP 276C also includes NMEA input with support forthe BWC, DBT, DPT, DSC, DSE, MTW, VHW, VTG, and XTEsentences.Garmin’s proprietary communication protocol is available from theWeb site (www.garmin.com).Removing the GPS AntennaYou can remove the GPS antenna to use an external antenna. Afterthe antenna is removed, the BNC connector is exposed and readyfor use with an external antenna. For information on connectingan external antenna to the GPSMAP 276C, refer to the installationinstructions that came with the antenna.To remove the GPS antenna:1. Remove the external power cable from the connector on theback of the GPSMAP 276C.2. Rotate the antenna to approximately a seven o’clockposition. The alignment notches in the casing must line upwith the notches on the antenna.3. Pull the antenna away from the GPSMAP 276C unit.Removing the GPS Antenna106 GPSMAP 276C Owner’s ManualAPPENDIX > INSTALLATION INFORMATION
