1. Receiver Audio Switches
2. Transmitter Selector Switch
3. AUDIO SPKR Switch
4. AUDIO EMER / NORM Switch
5. INTPH/OFF Switch
6. VOICE / RANGE / BOTH Switch
7. CABIN ADF Switch
8. Public Address Volume Control
9. Headphone Volume Control
10. Cockpit Speaker Volume Control
11. MKR BCN/VOL Control
12. MKR BCN HI / LO / TEST Switch
13. Compass System Selector Switch
14. DME HOLD Switch
15. DME/TAC Volume Control
Figure 3C-2. Audio Control Panel T2
(k) ADF 2 Switch Permits monitoring
of ADF 2 audio.
(l) MLS Switch Non-functional.
(m) Unmarked Switch Non-functional.
(2) Pilot and Copilot Transmitter-Selector
Switches. The pilot and copilot are each provided with
a transmitter-selector switch. These switches connect
the user's microphone and headset to the selected
regardless of the position of the respective receiver
(a) INTPH. When the pilot's or copilot's
transmitter selector switch is set to the INTPH position,
the pilot at that station is able to talk to the other pilot
by pressing his microphone switch and speaking into
his microphone. He will not be able to receive the
other pilot's intercom transmission unless the other
pilot's transmitter/selector switch is also set to the
INTPH position, or the INTPH/OFF switch is in the
interphone position and the audio speaker switch is in
the OFF position.
(b) PA Setting the transmitter selector
switch to the PA (public address) position allows the
pilot at that station to speak through the four cabin
speakers when his microphone is keyed. Talking
through the PA speakers will override cabin ADF
(c) VHF 1. Setting the transmitter
selector switch to the VHF 1 position routes key and
microphone signals to the number 1 VHF transmitter.
(d) VHF 2. Setting the transmitter
selector switch to the VHF 2 position routes key and
microphone signals to the number 2 VHF transmitter.
(e) HF. Setting the transmitter selector
switch to the HF position routes key and microphone
signals to the HF transmitter.
selector switch to the UHF position routes key and
microphone signals to the ARC-210 transmitter.
(3) Pilot and Copilot AUDIO SPKR Switch.
The pilot and copilot are each provided with a switch
placarded AUDIO SPKR/OFF, located on the pilot's
and copilot's side of the audio control panel, which
provide a means of controlling audio to the respective
pilot's and copilot's speaker system. When either of
these switches is set to the SPKR position, audio is
applied to the respective speaker system. When set to
the OFF position audio is removed from the respective