GMA
340 Installation Manual
Page B
-11
(Page B
-12
blank)
190-
001
49
-01
Rev L
Figure B5. J2 INTERCONNECT WIRING DIAGRAM
AIRCRAFT
GND
AIRCRAFT
GND
J2
PTT
5A
1
31
16
2
4
3
34
33
32
35
36
37
38
39
40
41
42
24
23
25
27
26
28
44
43
13
14
20
21
12
17
19
18
8
9
10
11
5
6
7
15
22
29
30
13A.
14.
W
H
EN
NO
AIRCRAFT
RADIO
ACT
IVIT
Y
IS
D
ET
ECT
ED
BY
T
H
E
G
M
A
340,
T
H
E
A
M
O
UNT
O
F
AM
BIENT
BACKGRO
UND
NO
ISE
FROM
T
H
E
R
ADIO
S
IS
F
URT
HER
R
EDUCED
BY
T
H
E
M
ASQ
CIRCUIT
.
IF
T
H
IS
FUNCT
ION
IS
NOT
DESIRED,
T
H
EN
J
1
PIN
16,
M
ASQ
INH
SHOULD
BE
T
IED
T
O
G
ROUND.
T
HIS
NOT
E
DOES
NOT
APPLY
T
O
T
H
E
FOLLO
W
ING
GM
A
340
SERIAL
NUM
BER
S:
9
4900
000
T
O
9
4900
499
AND
9
6250
000
T
O
96
25039
9.
15.
16.
2
S
T
A
GE
M
O
M
E
NT
ARY
SW
IT
CH.
FIRST
D
E
T
ENT
:
KEY
ED
INT
ERCOM
.
SECOND
DET
ENT
:
M
ICROPHONE
AUDIO
AND
P
T
T
ACT
IVE.
PROVIDE
S
K
EY
ED
INT
ERCOM
IN
HIGH
NOISE
ENVIRONM
ENT
S.
Headset L
MICROPHONE LO
340,
340H
IF GENERA
L AV
IATION MONOPHONIC HEADSET
S HAVING
TRUE MONOPHONIC PLUGS
ARE
USED IN
AN INSTALLATION
HAVING ST
EREO HEADPHONE
JACKS,
THE RING
CO
NDUCT
O
R
WILL BE
SHORTED
TO
THE BARRE
L CONDUCTOR
WHEN
THE HEADSET IS
PLUGGED IN.
T
H
IS WILL
NOT DAMAGE
THE
GMA 340.
HOWEVER, THIS
WILL PREVENT PROPER
FAILSAFE OPERATION. ADDITIONALLY
, SINCE THE PASSENGER HEADSETS ARE CO
NNE
CTED
IN PARALLEL, ALL
PASSENGERS WILL
LOSE
ONE CHANNEL IF
A MONO
HEADSET IS
PLUGG
ED INTO
A PASSENGER POSITION.
TO AVOID
THIS,
STEREO/MONO
SWITCHES
MAY BE INST
ALLED AS
S
H
O
W
N BELOW.
WHEN A MONO HEADSET IS USED,
T
H
E
SWIT
CH
MUST BE SET
T
O
THE OPEN POSITION.
SECOND DETENT, FULL ACTIVATION (TX)
FIRST DETENT, (ICS)
MICROPHONE HI
MIC RETURN
MIC KEY
MIC
Switch open for mono
Headset Return
Headset R
NOTES PERTAINING
TO J1 AND J2 (Cont
’d)
GMA 340
See note 15
See note 4
See note 4
See note 4
See note 12
Aircraft Power Buss
Mute Trigger to EXT PA
See note 6
See note 9
See note 8
See note 7
Cabin Speaker
PILOT HEADSET RETURN
PILOT HEADSET R
PILOT HEADSET L
14V LGT LO / 28V LGT LO
14V LGT HI / 28V LGT HI
COM TX MUTE
NC
NC
HI MUSIC GAIN SELECT
14V LGT HI / 28V LGT LO
(RESERVED, do not use)
TONE ENABLE
8 OHM SELECT
PA MUTE
COPILOT HEADSET RETURN
COPILOT HEADSET R
COPILOT HEADSET L
COPILOT MIC KEY*
COPILOT MIC RETURN
COPILOT MIC IN
PASS 1 MIC RETURN
PASS 1 MIC
PASS 4 MIC RETURN
PASS 2 MIC RETURN
PASS 2 MIC
PASS 3 MIC RETURN
PASS 3 MIC
PASS 4 MIC
MUSIC 1 RETURN
MUSIC 1 R
MUSIC 1 L
MUSIC 2 RETURN
MUSIC 2 R
MUSIC 2 L
SPKR RETURN
SPKR OUT
ICS MUTE INHIBIT
ICS MUTE INHIBIT RETURN
SWAP RETURN
SWAP
AIRCRAFT PWR
AIRCRAFT PWR
See note 17
17.
CONNECT TO
GROUND FOR
TIMES TEN
(20 dB)
GAIN,
OR INSTA
LL SWITCH TO
SELECT BETWE
EN
UNITY GAIN (0
dB)
AND
T
IMES TEN GAIN (20
dB) FOR
MUSIC1 AND
MUSIC2.
THIS FUNCTION
AP
PLIES
ONLY TO UNITS WITH MOD
5
INCORPORAT
ED.
T
H
IS
NOT
E
APPLIES
O
NLY
T
O
UNIT
S
CONFORM
ING
T
O
M
O
D
LEVEL
1.
NORM
AL
M
O
DE:
W
HEN
T
HIS
PIN
IS
TI
E
D
TO
GR
OUND,
T
R
ANS
M
IT
T
ING
(KEY
ING)
ON
ANY
C
O
M
W
ILL
CAUSE
T
H
E
O
T
HER
T
W
O
COM
AUDIOS
T
O
BE
M
U
T
E
D
DURING
T
H
E
T
RANSM
IT
.
S
P
LIT
COM
M
ODE:
W
H
EN
T
HIS
PIN
IS
T
IED
T
O
G
ROUND,
NEIT
HER
C
O
M
1
AUDIO
N
O
R
COM
2
AUDIO
W
ILL
B
E
M
U
T
E
D
DURING
ANY
T
RANSM
IT
.
COM
3
A
UDIO
W
ILL
O
NLY
BE
M
U
T
E
D
W
HEN
T
H
E
PILOT
T
R
ANSM
IT
S
.
NOTE 13A
APPLIES TO GMA 340
UNITS WITHOUT MOD
4.
NOTE 13B APPLIES TO
GMA 340 UNITS
WITH
MOD 4.
13B.
IF UNIT MOD
4
IS INCORPORATED,
T
H
E
ABOVE CONDITIONS STILL REMAIN EXCEPT THAT MOD
4 ENSURES PROPER
FA
ILSA
FE
OPERAT
ION FOR
BOTH STEREO AND MONO HEADSETS WITHOUT REQUIRING A
ST
EREO/MONO
SWITCH.
