Garmin 400/500 Owner's Manual page 55

dSC—turn DSC (Digital Selective Calling) on or off.
aiS alarm—turn a safe zone around your boat on or off. This is
used for collision avoidance, and the zone can be customized.
To customize safe-zone settings:
From the Home screen, select
Alarm.
• Range—change the measured radius of the safe-zone ring to
a specified distance from 500 ft. to 2.0 nm (or from 150 m to
3.0 km, or from 500 ft. to 2.0 mi).
• Time to (Safe Zone)—sounds an alarm if AIS determines that
a target will intersect the safe zone within the defined time
interval (from 1 to 24 minutes).
• AIS Alarm—when On is selected, a message is displayed
("AIS: Dangerous Target") when a vessel enters the safe
zone. When Off is selected, the message will not be
displayed.
GPSMAP 400/500 Series Owner's Manual
Configure > Other Vessels > AIS
Configuring the Chartplotter
49