Garmin GPSMAP 400 - Manual (Page 9)

GPSMAP 400/500 Series Owner’s Manual
Getting Started
Time Zone—set the time zone you want displayed for time
readings. If auto is selected for the Time Zone, the DST option is
not available and is automatically set to auto.
System Units—specify units for on-screen measurements as
Statute, Metric, or Nautical, or select Custom to individually
define units of measure for depth, temperature, distance, speed,
elevation, volume, and pressure.
Minimum Safe depth—select the minimum safe depth for your
boat. Refer to your boat specifications for more information.
Shallow water alarm—only available if you are receiving NMEA
sonar depth data. Select yes or No .
Minimum Overhead Clearance—select the minimum overhead
clearance for your boat. Refer to your boat specifications for more
information.
aiS alarm Range—select the distance at which an alarm will
sound if an AIS vessel nears your boat ( page 55 ).
aiS alarm Time To—select the time within which an alarm will
sound if an AIS vessel is on track to intersect the Safe Zone around
your boat ( page 55 ).
If a water speed wheel is detected, a message will ask if you want to
calibrate it now. Select yes or No .
Adjusting the Backlight
1. Press and release the Power key.
2. Press left or right on the Rocker to adjust the brightness.
To allow the unit to automatically adjust the backlight based on
ambient light, select auto backlight (automatic backlight is
available only on the GPSMAP 526 and 556).