WamBlee W402 VHF MSLD Manuel D'instruction page 36

Installation
The W402 receiver is designed to be installed in any vessel premises,
exception made for the areas where humidity level is more than 80%. The
device is not waterproof so it is necessary to choose a right position where
it will not be subject to water jets.
The device can be intalled both on a wall and on a plane surface, thanks to
its adjustable base (see picture 3).
On the back-side of it (see picture 4) there are 4 connectors, used in order
to:

connect a coaxial cable for the antenna (SMB connector);

connect a NMEA 0183 multi-function extension (terminal board)
EN

connect any acoustic or siren light type indicator (optional
terminal board)

feed the device (terminal board)
In picture 5 you can see an istallation example of the W402 receiver,
complete with connection to an outside alarm indicator.
Keyboard controls
On/Off
By pressing the ON-OFF button, for at least one second, you switch on or
off the W402 receiver. During the receiver switching on, every light
indicator is activated in order to verify that they work properly. After
switching on, the receiver will automatically set in listening mode.
Channel change
This button allows you to select 3 different reception frequencies, as per
the below table. Each time you press the button, the corresponding LED
will switch on. If you select a different frequency from the standard one for
the MOB devices (121.5 MHz), the receiver will syntonize again on the
emergency frequency after 2 minutes from the last selection.
Led on
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Frequency