External Power ........................................................................... 52Navigator Grounding. ................................................................ 53MX421 GPS ANTENNA INSTALLATION ........................................... 53Antenna Location ....................................................................... 53Antenna Options ........................................................................ 53Antenna Connector .................................................................... 53Antenna Cable Options .............................................................. 54External Differential Connection ................................................ 54MX420 NAVIGATOR INSTALLATION ................................................ 54Gimbal Mounting ....................................................................... 55Flush Mounting .......................................................................... 55Flush Mount Frame .................................................................... 55Turning Power On and Off ......................................................... 55EQUIPMENT INTERFACING ........................................................ 56Introduction .......................................................................... 56External Man Over Board & Event (MX420/8 Only) ............ 56Speed Over Ground Pulse Output ....................................... 57External Alarm Output ......................................................... 57Port 2: RS- 422 / RS- 232 Serial Interface ............................ 58MX420 PC Interface .............................................................. 59NMEA Interface .................................................................... 59NMEA Interface to other Equipment ................................... 60MX420 NMEA 0183 Sentences ................................................... 61Data Format .......................................................................... 61NMEA Output Sentences ..................................................... 62Input NMEA 0183 Sentences ............................................... 63Viewing Input Data ............................................................... 64Dual Control (Remote) Interface ................................................. 65MX420 Dual Control with Integrity Monitor .............................. 67Other MX420/AIS Interface .................................................. 68MX420 AIS Basic configuration .......................................... 69MX423 AIS Transponder Interface ....................................... 69Troubleshooting Guide .............................................................. 69Memory Backup Battery ............................................................ 71Backup Battery Replacement ..................................................... 71MX420 PC Interface .................................................................... 71Software Download Procedure .................................................. 71Memory Clear Procedure: .......................................................... 72