Beechcraft C-12C, Operator And Technical Reference Manual

Page: 356 / 949

TM 1-1510-218-10
Section II. COMMUNICATIONS
3C-4. DESCRIPTION.
The communications equipment group consists
of an interphone system, V/UHF, VHF, and HF
communications transceivers, and an ELT.
3C-5. MICROPHONE SWITCHES, MICROPHONE
JACKS, AND HEADSET JACKS.
Refer to Chapter 3, Paragraph 3-5, for
information on microphone switches, microphone
jacks, and headset jacks.
3C-6. AUDIO CONTROL PANEL T .
a. Description . Individual audio control panels,
part of the radio panel, are provided for the pilot and
copilot. The controls and switches provide for a
selection of transmission on V/UHF, VHF, or HF
transmitters and volume control of communication,
navigation, and interphone audio signals. Figure 3C-1
illustrates the pilots and copilot’s audio control panel.
b. Controls and Functions.
(1) PILOT/COPILOT AUDIO OFF Switches
– Permits monitoring of selected audio regardless of
position of transmitter selector switch.
(a) VHF 1 – Permits monitoring of #1
VHF audio.
(b) VHF 2 – Permits monitoring of #2
audio.
(c) HF – Permits monitoring of HF
audio.
(d) UHF – Permits monitoring of V/UHF
audio.
(e) NAV 1 – Permits monitoring of #1
NAV audio.
(f) NAV 2 – Permits monitoring of #2
NAV audio.
(g) MKR BCN 1 – Permits monitoring of
1 and 2 marker beacon audio.
(h) MKR BCN 2 – Permits monitoring of
2 marker beacon audio.
(i) DME/TACAN – Permits monitoring
of DME / TACAN audio.
(j) ADF 1 – Permits monitoring of #1
ADF audio.
(k) ADF 2 – Permits monitoring of #2
ADF audio.
(2) Copilot’s Transmitter Selector Switch –
Controls operation of selected system.
(a) VHF 1 – Routes key and
microphone signals to the #1 VHF transceiver.
(b) VHF 2 – Routes key and
microphone signals to the #2 VHF transceiver.
(c) HF – Permits reception of audio from
the HF transceiver and routes key and microphone
signals to the HF transceiver.
(d) UHF – Permits reception of audio
from the UHF transceiver and routes key and
microphone signals to the UHF transceiver.
(e) PA – Permits cabin paging.
(3) Copilot’s AUDIO SPKR / OFF Switch –
Determines where selected audio will be heard.
(4) Copilot’s VOLUME Control – Controls
audio volume.
(a) PH – Adjusts volume of headset.
(b) SPKR – Adjusts volume of cockpit
speakers.
(c) PA / CABIN ADF – Adjusts volume
of cabin speakers.
(5) Copilot’s VOICE / BOTH / RANGE
Switch and VOL Control – Controls both voice and
range tone.
(a) VOICE – Kills range, allows voice
(ADF and VOR).
(b) BOTH – Allows both voice and
range (ADF and VOR).
(c) RANGE – Kills voice, allows 1020
Hz range tone (ADF and VOR).
(6) MKR BCN 1 and 2 HI / LO / TEST and
VOL Control Switch – Selects either sensitivity or
TEST function.
3C-2