Icom IC-M57 - Additional Features; Dimmer Function; Low Battery Indicator

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a 5 ADDITIONAL FEATURES
i Dimmer
The function display backlighting can be turned OFF
and ON with the DIMMER [DIM] switch.
Push [DIM] to turn the backlighting ON or OFF.
Mi Low battery indicator
A small ”b” appears in the function display warning
of a low battery condition. When this happens,
check the dynamo of your boat as well as your
battery and connections. The battery may need to
be replaced.