TM 55-1510-219-10
INTPH
(depressed to first detent) Keys
interphone facility, disregards
position transmitter selector
switch.
XMIT
(depressed full down) Keys facil-
ity selected by transmitter select
switch.
(2) Floorboard switches.
CONTROL
FUNCTION
MIC foot switch
Controls connection of selected
mic to audio system.
Held depressed
Connects selected mic to audio
system.
Released
Disconnects selected mic from
audio system.
(3) Subpanel jack selector switches.
CONTROL
FUNCTION
MIC HEADSET/
Selects microphone to connect
OXYGEN
to audio system switch
MASK
MIC HEADSET
Connects headset microphone to
audio system.
OXYGEN
Connects microphone of oxygen
MASK
mask to audio system.
Section II. COMMUNICATIONS
3-5. DESCRIPTION.
The communications equipment group is comprised
of an interphone system connected to individual Audio
Control Panels for the pilot and copilot which interface
with VHF, UHF and HF communication units.
3-6. AUDIO CONTROL PANELS (FIG. 3-1).
a. Description. Separate but identical audio control
panels serve the pilot and copilot. The controls and
switches of each panel provide the user with a means to
select desired reception and transmission sources, and
also a means to control the volume of audio signals sent
and received for interphone, communication and
navigation systems. The user selects between the UHF,
VHF and HF transceivers. Audio control panels are
protected by respective 2-ampere AUDIO PILOT and
AUDIO COPILOT circuit breakers positioned on the
overhead circuit breaker panel (fig. 2-26).
b. Controls and Indicators.
(1) Audio controls - Comm and Nav Radios (fig.
3-1).
CONTROL/
FUNCTION
INDICATOR
Master VOL
Controls sidetone volume to
control
headset. Also serves as final
volume adjustment for received
audio
from
any
source
before
admission to headset.
Comm radios
Each is combination rotary con-
audio controls
trol and "ON-OFF" push-pull
switch, permitting both receiver
selection and volume adjustment.
1
ON connects user's headset to
audio from VHF-AM transceiver
No. 1.
2
ON connects user's headset to
audio from VHF/AM/FM trans-
ceiver.
3
ON connects user's headset to
audio from command UHF
transceiver in use.
4
ON connects user's headset to
audio from HF or VOW trans-
ceiver in use.
5
ON connects user's headset to
audio from backup VOW trans-
ceiver.
NAV radios
Combination volume control
audio monitor
and "ON-OFF" switches for
controls
NAV receivers.
NAV-A
ON connects user's headset to
audio from VOR-1, VOR-2 or
set in use.
NAV-B
ON connects user's headset to
audio from TACAN or ADF set
in use.
(2) Microphone switches.
CONTROL
FUNCTION
Mic impedance
Two-position thumb-actuated
select switch (5
switch. Enables selection of in-
Ohm/150 Ohm)
terface circuit with best imped-
ence match to microphone used.
3-2
