Furuno FSV-30 Operator's Manual page 29

Note: In the default setting, the sub menu item INITIAL SETTING in the
OTHERS menu and some items in the INITIALIZATION menu are shown
in red. This means their items are locked to prevent accidental change of
setting. When you open one of these sub menus and select an item, the
message below appears. To change the setting of the selected item, select
YES and press the [MENU] key, and the dialog box for the item selected
appears. To escape, select CANCEL and press the [MENU] key. You may
wish not to show the message below, that is, release the setting protection
feature. For further details, see ITEM ATTRIBUTION on page 8-15.
THIS ITEM IS DEFINED AS NON-CHANGEABLE ITEM.
ARE YOUSURE TO CHANGE IT TO CHANGEABLE?
CAUTION
Caution for menu setting change
1. OPERATIONAL OVERVIEW
YES
NO
1-15