Details On Making The Connections - Bose A20 Aviation Owner's Manual

English Tab 2, 10
Helicopter (U174) connection diagram
Existing wiring to
helicopter intercom/
audio panel
Note: Barrel ground (gnd) refers to aircraft grounds.

Details on making the connections

The pinouts for the optional installed connector are detailed in the table below:
Pin number
1
2
3
4
Note: For stereo operation, connect the left and right channels to their respective positions. For
monaural operation, connect pins 3 and 4 together, and to the tip of the existing phone jack.
5
6
Note: If the microphone works on radio transmit but not through the intercom, check pin 6. It
may be incorrectly wired to the PTT segment of the microphone jack.
Comm Shield
Mic Shield
Note: The wires connecting pins 3 and 4 and pins 5 and 6 are shielded, twisted pairs with a
black wire shield termination exiting each pair. If the existing wiring is not shielded, connect the
shields to the existing audio wiring shields, or connect the shield from Comm L and Comm R
wire pair to audio ground.
Tab 3, 11 Tab 4, 12
WHT/BLU
WHT
BLU
WHT
BLK
RED
10-32
1/2A
V DC
Existing single 4-
prong jack
Color Purpose
Red V+IN: Headset power (10-32 VDC). Use a
1
a / amp circuit breaker.
2
Black GND: System ground. Connect to the existing audio ground.
White COMM L: Phone communication: Left.
Blue COMM R: Phone communication: Right.
White MIC HI: Microphone/Hi-audio. Connect to the portion of the
existing microphone jack that corresponds to the ring
position of a headset microphone plug. Do not connect to
the tip (PTT) segment.
White/ MIC LO: Microphone/Lo-ground. Connect to the portion of
Blue the microphone jack that corresponds to the barrel position
of a headset microphone plug.
Black Shield from Comm L and Comm R wire pair.
Black Shield from Mic Hi and Mic Lo wire pair.
Tab 5, 13
6 MIC LO
5 MIC HI
4 COMM R
3 COMM L
2 GND
1 V+IN
Barrel
(audio gnd)
Tab 6, 14 Tab 7, 15
I
1
/ amp fuse or
4
Tab 8, 16
NSTALLATION
33