Furuno GP-3500F - Manual (Page 211)

11. VIDEO SOUNDER OPERATION
11-39
11.20 Interpreting the Sounder Display
This section provides, using typical examples, the information necessary for
interpreting the sounder display.
Surface noise
AUTO C
58.6
m
17.6
0
20
40
60
80
Fish school
Sea bottom
5.6 °
C 10.0 kt
1'50"
50k
Color bar
Minute mark
Zero line
Typical single frequency display