12OperationUsing theGPS 16positioning, then 1-2 minutes afterwards. When WAAS dif-ferential correction has been received for enough satellites,the NMEA 0183 data will indicate the availability of a dif-ferential fix in the GPGGA sentence. To learn more aboutthe WAAS system, its satellite positions and current state ofdevelopment, visit the FAA web site (http://gps.faa.gov).InterfacesThe GPS 16 serial Port 1 interface protocol designis based on the National Marine Electronics Association’s(NMEA) 0183 ASCII interface specification, which is fullydefi ned in “NMEA 0183, Version 2.0” and the Radio Tech-nical Commission for Maritime Services “RTCM Recom-mended Standards For Differential Navstar GPS Service,Version 2.1, RTCM Special Committee No. 104”. Contactinformation to obtain copies of the NMEA and RTCM speci-fi cations may be found on page 5. The GPS 16 may also beconfigured to output NMEA 0183, Version 3.0 data. See thetechnical specifications for more information.Port 2 is designated for RTCM data input only. Outputon Port 2 is reserved for future use.The GPS 16 interface protocol also transmits additionalinformation using the convention of GARMIN proprietarysentences ($PGRMx). Complete information on GPS 16capabilities, data transfer, NMEA 0183 sentence formatsand descriptions can be found in the “GPS 16 TechnicalSpecifications” (190-00228-20). You may order a copy ofthese specifications from GARMIN or your GARMIN dealer,or you may also download a copy from the manuals sectionof the GARMIN web site at www.garmin.com/support/userManual.html.The GPS 16 Port 1 is capable of transmitting the follow-ing NMEA 0183 data sentences:GPALM, GPGGA, GPGSA, GPGSV, GPRMC, GPVTG,GPGLL, PGRME, PGRMF, PGRMT, PGRMV and PGRMBThe GPS 16 Port 1 is capable of receiving the followingNMEA data sentences:GPALM, PGRMI, PGRMC, PGRMC1, PGRMO andPSLIB.The following NMEAtransmitted sentences areenabled at the factory:GPGGA, GPGSA, GPGSV,GPRMC, PGRMB,PGRME, PGRMT andPSLIBF