Cessna 172P - Page 253

PILOT'S OPERATING HANDBOOK
SUPPLEMENT
I
AUDIO CONTR,OL PANELS
SIDETONE OPERAÎION
Cessna
radios are equipped
with
eidetono capability
(monitoring
of
the operator's
own
voice transmission).
lVhile adjusting speaker sidetone,
bo aware that
if the
sidetone
volume
levol is set too high,
audio
feedback
(squeal)
may
result when
transmitting.
When
the airplane
has
one or two transmitters,
sidetone is
provided
in
either
the speaker
or
headset
anytimo the COM AUTO selector switch
is
utilized. Placing
the COM
AUTO selector
switoh in the
OFF
position
will
elíminate sidetone.
Sidetone
internal adjustments are available to the
pilot
through the front of
the audio
control
panel
(see
figure 1).
When
the airplane
has three
tranemittors, sidetone will
be heard on
either the
speaker or
a headset
as selectod with
the AUTO
selector
switch.
Sidetone
may be
eliminated
by
placing
the AUTO
selector
switch in the
OFF
position,
and utilizing
the
indivldual audio solector switchos. Adjust-
ment of speaker
and headset
sidetone
volume can only be acoomplished
by
adjusting
the
sidetone
potentiometers
located inside
the audio
oontrol
panel.
NOTE'
Sidetone
is not available on HF'Transceiver
(Type
ASB-
12õ), when
installed.
OPTIONAL INTER,COM
SYSTEM
The
optional
intercom
systom is a
pilot
and copilot intercom
phone
system which
is only
offered
with the one
and
two transmitter
typo
audio
control
panel.
The
system incorporates
its own
audio amplifier
with
a
volume
control
(labeled
INT)
and a
"hot
mike" feature. The
intercom
system
is
used with
the headphones
only.
The
"hot
mike" feature
allows the
pilot
and copilot to communicate at
anytime through
their microphone/headeets
without
having
to
key the
mike. However,
they
must
key
the mike button
on their control
wheel to
transmit
over
the
aircraft's transceiver.
Sidetone
is
present
on the inter-
com system
when
the
AUTO
switch is in the PHONE
position.
NOTE
Any ambient
noise
attenuating typo
padded
headset and
boom
mike
combination
is not
compatible with
this sys-
tem.
3
ßo
May
1980