Garmin Cessna Caravan G1000 Manual

G1000
TM
audio panel pilot’s guide

Garmin G1000 Audio Panel Pilot’s Guide 190-00378-02 Rev. A
Record of Revisions
Revision Date of Revision Revision Page Range Description
A 12/01/04 6A-1 – 6A-17 Initial release.

Garmin G1000 Audio Panel Pilot’s Guide190-00378-02 Rev. A 6A-1
INTRODUCTION
6A.1 INTRODUCTION
This manual provides the pilot with a description of
the GMA 1347 and its operating instructions.
The Garmin GMA 1347 is an audio control panel and
marker beacon system. Pressing the audio panel keys
controls audio selection of COM, NAV, telephone and in-
tercom. LED annunciators indicate when a key function
is selected.
NOTE: This audio panel is intended to be used
only as part of the G1000 Integrated Cockpit
System.
The GMA 1347 includes a six-position intercom sys-
tem (ICS) with electronic cabin noise de-emphasis and
two stereo music inputs. Separate knobs for the pilot and
copilot/passenger control intercom audio level. The in-
tercom provides four selectable modes of isolation (All,
Crew, Pilot, Copilot).
A cabin speaker is available to listen to selected aircraft
radios. MASQ (Master Avionics Squelch) processing re-
duces ambient noise from the avionics inputs.
Each microphone input has an automatic squelch
threshold. Manual squelch is available by pressing the
MAN SQ key.
The GMA 1347 provides a digital recorder that can
play back up to two and a half minutes of COM audio.
Recording is automatic when a COM signal is received.
Playback is controlled by pressing the PLAY key. Play-
back can be stopped by pressing the MKR/MUTE key.
The unit controls marker beacon receiver audio and
features marker beacon audio muting.
As part of the G1000 Integrated Cockpit System, the
GMA 1347 also operates the display reversionary mode.
Two GMA 1347 audio panels can be mounted in an
aircraft. In dual panel installations, two (2) units can be
connected to the same radios.
CAUTION: When the GMA 1347 Audio panel is
turned OFF or is inoperative, certain autopilots
are affected. No warning tone is supplied when
the autopilot disengages and the middle marker
sense signal is not supplied.

Garmin G1000 Audio Panel Pilot’s Guide 190-00378-02 Rev. A6A-2
DESCRIPTION
6A.2 UNIT DESCRIPTION
The GMA 1347 features three (3) major groups of keys
as shown in Figure 6A.2.1:
• Communication keys
• Navigation keys
• Intercom system (ICS) keys
Each key is labeled to indicate the name of the func-
tion. The triangular key annunciator above the keys are
white when illuminated.
The knobs at the bottom of the unit control ICS volume
and squelch threshold levels. The small knob adjusts the
volume/squelch level for the pilot. The large knob ad-
justs the volume/squelch level for the copilot/passenger.
The red DISPLAY BACKUP button below the dual vol-
ume/squelch knob controls reversionary mode selection.
FRONT PANEL CONTROLS
• Transceiver audio selector keys
(COM1, COM2, COM3)
• Transmitter (audio/mic) selection keys
(COM1 MIC, COM2 MIC, COM3 MIC)
• Split COM key
(COM 1/2)
• Dedicated telephone interface key
(TEL)
• Passenger address key
(PA)
• Speaker key
(SPKR)
• Marker beacon receiver audio select/mute key
(MKR/MUTE)
• Marker beacon receiver high sensitivity key
(HI SENS)
• Aircraft radio audio selector keys
(NAV1, NAV2, ADF, DME, AUX)
• Intercom manual squelch key
(MAN SQ)
• Digital recording playback key
(PLAY)
• Intercom system (ICS) isolation keys
(PILOT, COPLT)
• Volume/squelch knob
(VOL/SQ)
• Reversionary mode button
(DISPLAY BACKUP)

Garmin G1000 Audio Panel Pilot’s Guide190-00378-02 Rev. A 6A-3
DESCRIPTION
Transmitters Transceiver Audio
Split COM Telephone
Marker Beacon/Mute
Passenger Address
Marker Beacon Signal Sensitivity
Speaker
VOL/SQ
Manual Squelch
Navigation Radio Audio
Reversionary Mode Control
Digital Recording Playback
Navigation Radio Audio
Figure 6A.2.1 Front Panel Controls
ICS Isolation
VOL Annunciation SQ Annunciation

Garmin G1000 Audio Panel Pilot’s Guide 190-00378-02 Rev. A6A-4
DESCRIPTION
TRANSCEIVERS
The GMA 1347 handles three different transceivers:
• COM1 MIC
• COM2 MIC
• COM3 MIC
NOTE: A push-to-talk (PTT) switch must be
pressed to transmit on the selected radio.
Each audio panel can accept up to six (6) microphone
inputs, allowing for a two-person crew and up to four (4)
passenger intercom stations in the aircraft.
MONO/STEREO HEADSETS
The GMA 1347 can accommodate up to six (6) head-
sets, pilot, copilot and up to four (4) passengers.
NOTE: The use of stereo headsets is highly rec-
ommended.
Use of a monaural headset in a stereo jack shorts the
right headset channel output to ground. A person listen-
ing on a monaural headset hears only the left channel in
both ears. If a monaural headset is used at one of the pas-
senger positions, any other passenger listening on a stereo
headset hears audio in the left ear only, unless the headset
has a mono/stereo switch that is set to mono.
UNMUTED/UNSWITCHED INPUTS
The unit provides four (4) unmuted/unswitched in-
puts that are always present on the headsets or speaker.
These inputs are the following aural warnings:
• ALTITUDE WARNING
• UNSWITCHED 1
• UNSWITCHED 2
• UNSWITCHED 3

Garmin G1000 Audio Panel Pilot’s Guide190-00378-02 Rev. A 6A-5
OPERATION
6A.3 UNIT OPERATION
POWER-UP AND FAIL-SAFE OPERATION
Power-up
The GMA 1347 performs a self-test during power-up.
All panel annunciator lights illuminate for approximately
two (2) seconds. Once the self-test is completed, the set-
tings are restored to the ones in use before the unit was
last turned off.
See the System Overview section for additional power
up information.
Fail-safe Operation
A fail-safe circuit connects the pilot’s headset and mi-
crophone directly to COM1 in case power is interrupted
or the unit is turned off. In this case, audio is not available
on the speaker.
SELECTING AND DESELECTING KEYS
LED annunciators indicate when a key function is se-
lected. Pressing a key activates and deactivates the func-
tion, turning the annunciator light on and off.
LIGHTING
LED key annunciators and backlighting are controlled
automatically by the G1000 Control Display Unit (CDU).
TRANSCEIVER KEYS
The following eight (8) transceiver keys appear at the
top of the GMA 1347 front panel: COM1 MIC, COM2
MIC, COM3 MIC, COM 1/2, COM1, COM2, COM3,
and TEL. COM audio can be selected by pressing either
the desired COM key or by pressing a COM MIC key.
Figure 6A.3.1 Transceivers
COM MIC Keys
Pressing the COM1 MIC, COM2 MIC or COM3 MIC
key selects the COM radio as the active transceiver. The
receiver audio key, COM1, COM2, COM3 is also select-
ed. The COM frequency is highlighted green in the active
frequency field of the PFD and MFD.
Only one microphone source can be selected at a time.
If COM2 MIC is pressed when COM1 MIC is active, the
unit switches to COM2.
COM Keys
Pressing the COM1, COM2, or COM3 receiver key
selects the COM radio as an active receiver source. Any
combination of radios can be selected separately or simul-
taneously regardless of the active transceiver selection.
The active COM radio is always heard through the head-
sets.

Garmin G1000 Audio Panel Pilot’s Guide 190-00378-02 Rev. A
6A-6
OPERATION
Transmitting
When a transmitter is keyed, the active transceiver
MIC key annunciator blinks approximately once per sec-
ond. A white TX indication appears next to the active
COM frequency on both the PFD and the MFD during
transmission.
NOTE: Audio level of the COM radio(s) is con-
trolled by the COM volume controls located on
both the PFD and MFD (see the VHF NAV/COM
Pilot’s Guide).
COM SWAP
A remotely mounted switch can be used to transfer the
active transceiver between COM1 MIC and COM2 MIC.
Pressing the switch has no effect if COM3 is the active
transceiver.
OPTIONAL COM MUTING
COM muting on receive and COM muting on trans-
mit options can each be disabled if desired. Contact a
Garmin-authorized service center for details.
COM Muting on Receive
When COM muting on receive is enabled, all second-
ary COM audio is muted during detection of received pri-
mary COM audio.
NOTE: If COM muting on receive option is
enabled, only primary COM radio reception is
recorded by the digital clearance recorder.
COM Muting on Transmit
When COM muting on transmit is enabled, all sec-
ondary COM audio is muted during transmission over the
primary COM radio.
TELEPHONE INTERFACE
The GMA 1347 contains a dedicated telephone inter-
face that is closely linked to the ICS operation. It is con-
trolled by the TEL key. See Table 6A.3.3 for a summary
of the telephone distribution and the various ICS isolation
modes.
NOTE: The ringer to the TEL channel is muted
during COM radio transmissions.
SPLIT COM FUNCTION
Pressing the COM 1/2 key selects the split COM func-
tion. During split COM operation, the COM1, COM1
MIC, COM2 and COM2 MIC keys are active.
When the COM 1/2 key is selected, COM1 is used by
the pilot for transmission and COM2 is used by the copi-
lot. The COM1 MIC annunciator blinks when the pilot’s
microphone is keyed and the COM2 MIC annunciator
blinks when the copilot’s microphone is keyed.
In this mode, both the pilot and the copilot can trans-
mit simultaneously over separate radios. The pilot can
still monitor COM3, NAV1, NAV2, DME, ADF, AUX and
MKR audio as selected, but the copilot is only able to
monitor COM2.
Split COM mode is cancelled by pressing the COM 1/2
key again.
NOTE: Split COM performance varies significantly
across installations and is affected by both the
distance between the antennas and the separa-
tion of the tuned frequencies.

Garmin G1000 Audio Panel Pilot’s Guide190-00378-02 Rev. A 6A-7
OPERATION
PA FUNCTION
A passenger address function is provided by pressing
the PA key. Push-to-talk (PTT) must be used to deliver PA
announcements over the headsets.
SPEAKER
All of the radios can be heard over the cabin speaker.
Pressing the SPKR key selects and deselects the cabin
speaker. Speaker audio is muted when the PTT switch
is keyed.
The speaker volume is adjustable above and below a
nominal value. Contact a Garmin-authorized service cen-
ter for details.
MARKER BEACON RECEIVER
Description and Operation
The GMA 1347 marker beacon is used as part of the
ILS system. The marker beacon receiver is always ON and
receives at 75 MHz. The GMA 1347 provides a marker
audio muting capability.
The receiver detects the three (3) marker tones, outer,
middle and inner, and illuminates the appropriate mark-
er beacon indicators. The marker indicators are located to
the left of the Altimeter on the PFD (Figure 6A.3.3). The
outer marker frequency is 400 Hz with a blue indicator,
the middle marker frequency is 1,300 Hz with an amber
indicator and the inner marker frequency is 3,000 Hz with
a white indicator. Refer to Table 6A.3.1 for a summary of
the marker beacon signal characteristics.
When the MKR/MUTE key is selected, the annun-
ciator light illuminates and the audio signal can be heard
over the speaker or headsets during marker reception.
When the MKR/MUTE key is annunciated and a mark-
er beacon tone is received, pressing the MKR/MUTE key
mutes the audio but does not affect the annunciators. The
audio returns when the next marker signal is received. If
the MKR/MUTE key is pressed during signal reception,
while marker beacon audio is muted, marker audio and
the MKR/MUTE key annunciator light are turned off.
NOTE: The marker beacon receiver lights operate
independently of the marker beacon audio and
cannot be turned off.
The marker beacon audio output level is adjustable by
a Garmin-authorized service center.
NOTE: The GMA 1347 is capable of driving
external marker beacon lamps.
Marker Beacon Signal Sensitivity
The HI SENS key can be pressed for increased marker
beacon signal sensitivity. The HI SENS function is used
to receive an earlier indication of nearing a marker during
an approach.
Figure 6A.3.2 Marker Beacon

Garmin G1000 Audio Panel Pilot’s Guide 190-00378-02 Rev. A
6A-8
OPERATION
Beacon Audio Frequency Audio Keying Rate Lamp Color
Outer Marker 400 Hz — — — 2 dashes per second Blue
Middle Marker 1,300 Hz • — • — 95 dot-dash combinations
per minute Amber
Airway/Inner Marker 3,000 Hz • • • • 6 dots per second White
Table 6A.3.1 Marker Beacon Signal Characteristics
Inner Marker Middle Marker Outer Marker
Figure 6A.3.3 Marker Beacon Signal Indicator Lights on the PFD