TruTrak KRT2 Comm Radio IR - Manual (Page 26)

4.3.1
Microphone
Connection
Both
the
L
(left)
and
R
(right)
microphone
input
channels
can
either
be
connected
to
standard
microphones
(standard
signal
level
1Vpp)
or
to
dynamic
microphones
(standard
signal
level
5mV
to
10mV).
For
standard
microphones
a
supply
voltage
of
8V
at
330Ω
is
provided.
Elementary
Electret
microphones
can
also
be
connected.
They
have
considerably
lower
signal
levels
and
therefore
require
an
8V
supply
voltage.
The
microphone
input
channel
amplifier
gain
can
be
selected
via
the
MIC
Setup
menu.
When
dynamic
microphones
are
used
in
gliders
the
8V
supply
voltage
is
switched
off
for
power
saving
purposes.
Standard
microphones
normally
used
in
headsets
together
with
dynamic
microphones
generally
cannot
be
used
at
the
same
time.
Motor
gliders
should
have
a
toggle
switch
installed
to
differentiate
between
motor
less
flight
with
dynamic
microphones
and
powered
flight
with
headsets.
When
the
AUTO
mode
is
selected
in
the
MIC-­‐Setup
menu
the
KRT2
automatically
recognizes
to
which
microphone
type
has
been
switched
and
acts
accordingly.
Because
the
8V
supply
voltage
is
switched
off
when
dynamic
microphones
are
used
during
glider
flight
the
second
(copilot)
headset
microphone
is
disabled.
A
maximum
of
two
microphones
of
same
type
may
be
connected
to
each
microphone
input
channel.
4.3.2
Earphone
Connection
Several
earphones
of
same
type
can
be
connected
in
parallel.
The
total
impedance
should
not
be
less
than
60
Ohms.
4.3.3
External
Audio
Input
Audio
alarms
or
even
music
can
be
made
available
via
the
external
audio
input.
When
this
input
is
not
used
it
must
be
connected
to
ground
in
order
to
avoid
noise.
PIN5
must
be
connected
to
Battery
minus
(GND).