Furuno FCV-1200L Operator's Manual page 47

EXT DEVICE
Selects the equipment to use for EX in use mode EX of SCREEN LAYOUT. "EXT" appears at the
top of the screen.
ETR: External Transceiver Unit
TS/OTHER: telesounder, external echo sounder, sonar, picture recorder.
Note: When selecting
should be connected to the EXT_H port. The EXT_L port signal cannot be displayed on
those screen layouts.
DEFAULT SET
Restores default settings of the user-1/2 menus. Select YES to restore default settings. Three
beeps sounds while default settings are being restored.
or screen, the above equipment (low frequency echo)
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