Lowrance SonicHub Marine Audio Server Mode D'emploi page 11

Operation
Audio Source
The Audio Source screen displays the menu of the selected audio source on your
unit's screen.
That allows you to make adjustments to an audio source using its native menu or
file structure (USB).
Selecting an audio source
You can use the SonicHub menu or your display unit softkeys
to select an audio source. You must select an audio source to
listen to SonicHub audio.
The Mic source selects a high voltage level input. It allows you
to broadcast loud hailer messages over the audio system by
replicating the loud hailer on the Lowrance LVR-880.
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