Furuno MFD8 Installation Manual page 34

Note: The MFDBB Ethernet Port1 and Port2 are dedicated to connect the BB Keyboard.
Leave these switches on OFF as the Keyboard does not need the Power
Synchronization signal.
DFF1/DFF3: The DFF1 has DIP switches that need to be set up differently if you use a
regular hub or the Furuno HUB101 (with Power Synchronization).
When you set up the Dip switches for the HUB101 (all dip switches in the UP position),
the DFF1 will NOT power ON until one MFD is powered on (until the Power
Synchronization Signal is received). If the Power Synchronization signal is not received
on the DFF1, the Power LED (green light) will not light up even if you apply 12-24V to
the unit. In this case make sure that you are using 4-Pair Ethernet cable and that the
Power Synchronization DIP switches inside the HUB101 and MFDBB (if applicable) are
ON.
If you are using a regular Hub that cannot pass the Power Synchronization signal, make
sure that the Dip switches are "Down-Up-Up-Down". In this configuration, the DFF1 will
power ON as soon as power is applied to the unit.
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