Garmin GPSMAP 721 Installation Instructions - Page 4

+ - > > > > Item À Á  Item Ê Ë Ï Í Description 12 Vdc power source Wiring harness NMEA 0183-compliant device Garmin Wire Function Garmin Wire Color Power Ground Tx Rx Red Black Blue Brown NMEA 0183 Device Wire Function Power Data ground Rx/A (+) Tx/A (+) Lamp or Horn Connections The device can be used with a lamp, a horn, or both, to sound or flash an alert when the chartplotter displays a message. This is optional, and the alarm wire is not necessary for the device to function normally. When connecting the device to a lamp or horn, observe these considerations. • The alarm circuit switches to a low-voltage state when the alarm sounds. • The maximum current is 100 mA, and a relay is needed to limit the current from the chartplotter to 100 mA. • To manually toggle visual and audible alerts, you can install single-pole, single-throw switches. Item Description À 10-35 Vdc power source Á Power cable  Horn à Lamp Ä Relay (100 mA coil current) Å Toggle switches to enable and disable lamp or horn alerts Item Ê Ë Ì Wire Color Red Black Yellow Wire Function Power Ground Alarm 4 NMEA 2000 Considerations NOTICE If you have an existing NMEA 2000 network on your boat, it should already be connected to power. Do not connect the included NMEA 2000 power cable to an existing NMEA 2000 network, because only one power source should be connected to a NMEA 2000 network. If you are installing the included NMEA 2000 power cable, you must connect it to the boat ignition switch or through another inline switch. NMEA 2000 devices will drain your battery if the NMEA 2000 power cable is connected to the battery directly. NMEA 2000 compatible models can connect to a NMEA 2000 network on your boat to share data from NMEA 2000 compatible devices such as a VHF radio. The necessary NMEA 2000 cables and connectors are sold separately.