Garmin GMA 340 Manual

GMA 340
Audio Panel
pilot's guide

Front Panel Controls (GMA 340)
Front Panel Controls (GMA 340 Dual ADF)
r) (z) (s) A 9iD (0 (6) Qt
/l\,
cm{n 1 *rr / r*.fi d::I
A O M ,HP co'l; coM2
ffi\ ,o o',,,/", rr-r:. r.Ti3
ilUJy ","r : r-o 'f,1[' "fl|['r
\i*-4 sENs
P/LOT\ r \. I
*fu I =\* d= GMA\340
r.rnv z I o* noiz TEST
u=r= ol= :umPrLor :i /m\
,"/*o*r'n ";. & L, J )
ffir pA AcREw ffi \m{
,, / I qOHLqf
d= \ lo*=
coM3 17'NAv1r
I
rrrrrr / r=s:
cou3 O
MtC SPKR
(z) (r i
:6) (a) (b o@o @
-5)
Front Panel Controls (GMA 340H)
t3

Function Selection Switches
The left small knob (5,7) on all unis controls ON/OFF function.
MKR
BCN
l. MarkerBeaconlamps
7. Marker Beacon ReceiverAudio Select/Mute Button
3. Markr Beacon Receler Sensitruty Indicator LED's
4. Marker Beacon Receiver Sensitivrry Selection Button
5. hlot Intercom System (lCS) Volume (Also PassengerVolume on 340H)
6. hlot ICS Voice Activated (VOX) lntercom Squelch Level
7 , Copilot and Passenger ICS Volume Control (putt out for PassengerVolume)
B. Copilot and PasengerVOX lntercom Squelch Level
9. Crew Isolation lntercom Mode Button
10. hlot Isolation lntercom Mode Button
1 l. Passenger Addres (PA) Function Button
12. Speaker Function Button
rcs
13. TiansceiverAudio Selector Buttons (CCltvt l, COM 2, COM 3)
COM/ 14. Transmitter(AudioA4ic) SelectionButtons
NAV 15. Split COM Button (NotAvailable inDualADF)
16. Aircraft Radio Audio Selection Buttons (NAV l, NAV 2, D\4E, ADF l, ADF 2)
17 . AnnuncntorTestButton
lB. Locking ScrewAcces
19. Photocell-AutomaticAnnunciatorDimming

On. Off. and Failsafe Operation
The GMA 340 is powered off when the lelt smallknob (5, 7) is rotated frlly CCW into the detent.
To tum the unit on rotate the knob clockwrse past the click. The left small knobs also lunctions as the
pilot or copilot's ICS volume control on the appropriate unit. A failsafe circuit connects the pilot's headset
and microphone directly to COM I in case the power is intemrpted or the unit is tumed off.
Lighting
LED Button annunciator and markerbeacon lamp intensity are controlled automatica\by a bulhin
photocell on the front panel. Nomenclature backlighting is controlled by the aircraft dimmer buss.
Transceivers
Audio level is controlled by the selected C)M radio volume control.
SelectionofeitherCOM I,COM Z,orCON4 3(13)forbothMlCandaudiosourceisaccomplished
by pressrng either COM I N4lC, CON4 2 N4lC, or COM 3 MIC (14). The active com audio rs always heard
on theheadphones.
Additiona\ each audio source canbe selectedindependentlybypressrry COM 1, COM 2,or COM 3
(13) When selected in this way,they remain active as audio sources regardless olwhich transceiver has
been selected formicrophone use.
When a microphone is keyed, the active [ransceiver's MIC button LED blinks appro]omately once per
second to indicate that the radio is transmittlng.
Split COM (Not Available on Dual ADFI
Pressingthe CON{ l/2 button (15) actlates the Sp1lt COM function. When this mode is active,
COM I is dedicated sole1y to the pilot lor Ml0audio while COM 2 is dedicated to the copilot for MIO
audio. The pilot and copilot can srmuhaneously transmit in this mode over separate radios. Both pilots
can still listen to COM 3, NAV l, NAV 2, DI\4E, ADE and MKR as selected. The Split COM mode is
cancelled by pressrng the CON4 1/2 button a second time.
When rn the Split COM mode the copilot may make PA announcements whrle the pilot continues
usrry COM I independently When the PAbutton is pressed after the Split COM mode is activated, the
copilot's mic is output over the cabrn speaker when keyed. A second prcss of the PA button returns the
copilot to normal spht COM operation.
lf the C)M radios utilize a "transmit interlock" system, the Split C)M
function may require that this feature is enabled. Refer to the radio's
installation manual for guidance. GARMIN makes no expressed or implied
guarantees regarding the suitability of the Split C)M feature in a given
installation,

Com Swap Function
The GMA 340 allows the use of a remote mounted swrtch (typically on the yoke) to altemately
ftansfer the actn e microphone back and forth between COM I and COM 2. Pressrng the remote swrtch
will have no affect if COM 3 is the active transceiver. Ask your installing agency for details.
Aircraft Radios & Navigation
Audio level is controlted by the selected NAV radio volume control.
Pressing NAV l, NAV 2, DME, ADF l, ADF 2(16),or MKR (2) (see MKR Beacon Receiver, page B)
selects each audio source. A second button press deselecs the audio.
In addition, rhe GMA 340 provides inputs for an unswrtched aircraft radio (TEL RINGER) and an
unmuted, unswitched aircraft radro (ALTWRN).
Speaker Output
Pressing the SPKR button ( l2) selects aircraft radios over the cabin speaker. The speaker output is
muted when a COM microphone is keyed. The GMA 340 speaker output level can be adjusted by your
installing agenq{
PA Function
The PA mode is actwated by pressing the PA button ( I l). Then, when either the pilot's or copilot's
microphone is keyed, the conesponding mic audio is heard over the cabin speaker. If the SPKRbutton is
also actle, rhen any selected speaker audio is muted while the microphone is keyed. The SPKRbutton
does nothaveto be prer,,rously active in order to use the PA function. Pilot and copilot PA microphone
speaker levels are adjustable by your installing agency
Auxiliary Entertainment lnputs
The GMA 340 and340H provrde two stereo entertainment rnpus: MUSIC I and I\4USIC 2. The340
Dual ADF has only MUSIC l. MUSIC I is sofrmuted during all aircraft radio activtty and norma\
dunng ICS actrvrty MUSIC 2 is a non-muted input. These inpus are compatible with popular portable
entertainment der,rces such as cassette tape or CD players. The headphone outputs of these der,rces are
used ancl plugged into MUSIC I or MUS IC 2 . Two 3. 5 mm stereo phone jacks should be installed in a
convenient location for this purpose. MUSIC I and MUSIC zhave charactenstics that are allected by the
active rntercom mode. Refer to the table on page 7.

340H)
Inrercomvolume andsquelch (vox) are adjustedusingthe followingfrontpanel knobs:
o LEFT SMALT KNOB - Unit oN/oFF power control and Pilot lcs volume. Full
CCW DETENT Position is OFE
o LEFT LARGE KNOB - Pilot lcS mic VoX squelch level. cw rotation increases the
amounr of mic audio (VOX level) required to break squelch Full CCW is the "hot mic"
position.
o RIGIIT sMALt KNOB - lN position: Copilot ICS volume. ouT position:
Passenger ICS volume.
o RIGHT IIIRGE KNOB - Copilot and passenger mic VOX squelch level. CW
roration increases rhe amount of mic audio (VOX level) required to break squelch. Fully
CCW is the "HOT M lC" Position.
Each of the sixmicrophone inpushave dedicatedVOXcircuisensuringthat only the active
microphone(s) iJare heard when quelch is broken. This represents a vast rmplovement over the party-
line qrstems and reduces the amount of background noise in the headphones during cockpit communica-
tions Aftertheoperatorhasstoppedtalking,theintercomchannelremainsmomenUrilyopentoavoid
closure between words or normal pauses.
The GMA 340 prrtvides rhree intercom modes: Pllot GREW and ALL. The mode selection is
accomplished usrngthe PILOT and/or CREWbuttors.
Pressrng a mode button activates the corresponding ICS mode. Pressing again deactivates the mode'
Th.op.*toi.unswitch direcdyfromPILOTto CREWorfrom CREWto PllOTbypressrngtheother
rodebuuon. The ALL mode L active when neither PILOT nor CREW LED are lit. To switch from
PILOTtoCREWmode,prestheCREWbutton;fromCREWtoPILOIpressthePILOTbutton AnLED
ON indicates the isolationmode is active.

o PILOT moileisolates the pilot from everyone else and dedicates the aircraft radios to the
pilot exclusively The copilot and passengers share communication between themselves but
cannot communicate wrth the pilot or hear the aircraft radios.
o CkfJf moileplaces the pilot and copilot on a common ICS communication channel.
The passengers are on their own intercom channel and can communicate with each other, but
cannot communicate wrth the crew or hear the aircraft radios.
o ,4LLmade allows full intercom communication between everyone plugged in to the GMA
340. Aircraft radios are heard by all.
o MUSIC I andMUSIC2 stereo entertainment inputs are affected by the intercom mode
selected.
The following table summarizes the ICS operation for the different modes supportedby the
GMA34O:
MODE PILOT HEARS COPILOT HEARS PASSENGER
HEARS
MUSIC I MUTING
TRIGGERED BY
PILOT
(LED
LIT)
Selected Radios.
Pilot
Copilot.
Passengers.
MUSIC 1
Passengers.
Copilot.
MUSIC 1
Copilot or passenger
ICS activity,
CREW
(LED
LrT)
Selected Radios.
Pilot.
Copilot.
MUSIC 1
Selected Radios,
Copilot Pilot.
MUSIC 1
Passengers.
MUSIC 2.
(MUSIC 1 in Dual
ADF)
Aircraft radio activity.
MKR activity.
Pilot or Copilot ICS
activity.
ALL
LED,S
0FF)
Selected Radios.
Pilot.
Copilot.
Passengers.
MUSIC 1
Selected Radios.
Pilot.
Copilot.
Passengers.
MUSIC 1
Selected Radios.
Pilot,
Copilot.
Passengers.
MUSIC 1
Aircraft radio activity
MKR activity,
ICS activity.
MUSIC t is normally muted during ICS activity However an installation option is available to disable
ICSMUTE. ThenmutingofMUSlC lwillnotoccurduetolCSactMty Apanelmountedswitchmaybe
installed for this function. The MUSIC I mute trip 1evel is adjustable by the installing agency
Mono/Stereo Headset
The use of stereo headses is highlyrecommended.
lf monaural headsets are plugged into stereo jacks that do not have a switch
installed, the unit will not be damaged.
lf the pilot uses a monaural headset in a stereo jack, no audio will be heard
during failsafe operation. When using a monaural headset the pilot's jack must
be equipped with a stereo/mono switch and it must be set to the 'mono' position
for proper failsafe operation,
A penon listening on a monaural headset will hear only the left channel from the GMA 340 in both ean. If
a monaural headset isused at one o[thenassenserrnsitions. anvothernassenserlisteninson astereoheadset
6
@

Limited Warranty
GARMIN Corporation wanants this product to be free from defects in materia]s and worlcnarship for
one year from the date of purchase. GARMIN will, at its sole option, repair or replace any components
which fail in normal use. Such repairs or replacement will be made at no charge to the customer for parts
or labor. The customer rs, however, responsible for any fianspofiation costs. This wananty does not
cover failures due to abuse, misuse, accident or unauthorized alteration or repairs.
THEWARMNT'IESANDREMEDIES CONTAINED HEREINARE EXCLUSMAND IN UEU OFALL
OTHERWARMNTTES EXPRESSED OR IMPUED, INCLUDINGAM LIABIUTYARISING UNDER
WARMNTY OF MERCMNIABILITY OR FITNESS FORA PARNCULARPURrcSE, STAruTORY OR
OTHERWSE. THIS WARRANTY GNES YOU SPECIFIC LEGAL RIGHTS, WHICH MAYVARY FROM
STAIETOSTAIE.
IN NO EVENTSLIALLGARMIN BE L]ABLI FORAMINCIDENTAL, SPECIAL, INDIRECTOR
CONSEQUENT'IALDAMAGES,WHETHERRESULT'INGFROMTHEUSE,MISUSEORINABIUTYTO
USE THIS PRODUCTORFROMDEFECTS lN THEPRODUCT. SOME STAIES DO NOTALLOWTHE
EXCLUSIONS OF INCIDENTAL ORCONSEQUENTIAL DAMAGES, y) TTtrABO\E UMITANONS MAY
NOTAPPLYTOYOU.
To obtain wananty sewice, call the GARMIN Customer Service department (9131397 .8200) for a
retumedmerchandise trackingnumber. The unitshouldb securelypackagedwith the trackingnumber
clearlymarkedon the ouside of thepackage, andsentfreightprepaidandinsuredto a GARMINwananty
service station. A copy ofthe origrnal sales receipt is required as the proofofpurchase forwananty
repalrs. GARMIN retains the exclusive right to repalr or replace the unit or software or offer a fulIrefund
of the purchase price at lts sole discretlon. SUCH REMEDY SFIALL BE YOUR SOLE AND EXCLUSM
REMEDY FORAM BREACH OF WARRANTY.