2
Button description
Indication LEDs:
Yellow flashing
：
There are input pulses, which is to have been connected with
echo sounder/ fish finder with power on.
Red flashing: There are output single, which is to send to bottom/fish signal.
Power on/off: Turn on/off the system.
Operation Area
：
To move the cursor position
To set values
To echo transmit/pause and test start/pause
To return to previous menu
To enter the selected menu.
External connector
：
Five-core socket for connecting echo sounder or transducer
When transducer test of SIM990
is on, the transducer cannot be
connected with the main unit and
the cable for transducer tester
must be used.
