USING THE 250DX
MENU FUNCTIONS
Automatic Zoom is especially helpful when looking for structure or bottom detail. The Automatic Zoom keeps the bottom in view even in quickly changing terrain, but is most useful in flatter areas without considerable depth variation. Manual Zoom provides detailed information of any area from the surface to the bottom. In manual Zoom, the Zoom range does not move as the terrain changes.
When the range is shown in the menu, the upper 
number represents the top of the current Zoom 
range. The lower number represents the bottom of 
the Zoom range. Use the UP and DOWN ARROW 
buttons to move this range. The upper number can 
never be less than 0 (the surface of the water), and 
the lower number can never be greater than the 
active depth range. The difference between the 
two numbers (the Zoom range) is preset and 
determined by the active depth range.
Once manual Zoom is selected, the display 
appears the same as in Auto Zoom, but the zoom 
range does not change automatically. 
To disable Zoom, press the MENU button until the 
Zoom menu is 
highlight Off, and let the menu time out. 
When the unit is powered off, the Zoom menu 
returns to Zoom Off.
Depth Alarm. The 250DX contains an audible 
alarm to warn you of shallow water depths. The 
alarm is adjustable to depths of 1m (3') to 30m 
(99'). When the alarm is enabled, an audible 
alarm sounds if the water beneath the boat is 
equal to or less than the selected alarm depth. 
The alarm sounds continuously for about five 
seconds, and then intermittently to remind you 
that you are still in shallow water.
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