Raymarine GPM400 Reference Manual page 106

Frequency 1 Behaviour
DSM400 AUTO Automatically
adjusts to suit
depth.
MANUAL Fixed at
selection.
AUTO Automatically
selects highest
frequency and
widest beam.
DSM300 AUTO Changes with
depth; alter-
nate pings of
50 Khz and
200 Khz.
AUTO Changes with
depth; alter-
nates between
50 Khz and
200 Khz.
AUTO Frequency set
to 200 Khz.
G-Series Reference Manual
Frequency 2 Behaviour
NONE/MAN Manual setting
is fixed.
NONE/MAN Manual setting
is fixed.
AUTO Automatically
adjusts to suit
depth.
MANUAL Fixed at
selection.
NONE -
AUTO Frequency set
to 50 Khz.
106