®
A20 AVIATION HEADSET
Owner’s Guide
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English
SAFETY INFORMATION
NOTE: This equipment has been tested and
Important Safety Instructions
found to comply with the limits for a Class B
digital device, pursuant to Part 15 of the
FCC Rules. These limits are designed to
provide reasonable protection against
harmful interference in a residential
•
Please read these instructions carefully
and completely before using the headset.
•
Keep these instructions and make these
instructions easily accessible to all users
at all times. Always include these
instructions when passing the headset
on to third parties.
installation. This equipment generates, uses,
and can radiate radio frequency energy and,
if not installed and used in accordance with
the instructions, may cause harmful
interference to radio communications.
However, there is no guarantee that
interference will not occur in a particular
installation. If this equipment does cause
harmful interference to radio or television
reception, which can be determined by
turning this equipment off and on, the user is
encouraged to try to correct the interference
by one or more of the following measures:
•
•
During flight operations, do not use the
headset for telephone calls.
It is the responsibility of each aircraft
operator or pilot in command to
determine that any and all portable
devices will be free of any interference
with the navigation or communication
system of the aircraft. In addition, it is
their responsibility to determine the
suitability of the performance of portable
devices in relation to the use of the
Bose® A20® Aviation Headset.
– Re-orient or relocate the receiving
antenna.
– Increase the separation between this
equipment and receiver.
– Connect this equipment into an outlet on
a circuit different from that to which the
receiver is connected.
– Consult Bose or an experienced radio/TV
technician for help.
Changes or modifications not expressly
approved by Bose Corporation could void
the user’s authority to operate this
equipment.
•
The headset is capable of producing
sound pressure levels exceeding
85dB(A). In many countries 85dB(A) is
the maximum legally permissible level for
continuous noise exposure during the
working day. Exposure to sounds of
higher volume levels or longer durations
can permanently damage your hearing.
•
•
•
•
Never repair or attempt to repair a
defective headset yourself. Contact
Bose® Technical Support. Refer to
“Contact information” on page 37.
Operation is subject to the following two
conditions: (1) This device may not cause
harmful interference, and (2) this device
must accept any interference received,
including interference that may cause
undesired operation.
Do not immerse the headphones in water
or any other liquid. See “Cleaning the
headset” on page 23 for cleaning
instructions.
Warning: Choking
hazard. Keep the
batteries away from
children.
This device complies with FCC and Industry
Canada RF radiation exposure limits for
general population. It must not be collocated
or operating in conjunction with any other
antenna or transmitter.
Danger of explosion if
batteries are incorrectly replaced.
Replace only with AA alkaline
batteries. Do not use any other
battery chemistries.
Batteries may cause a fire or chemical
burn if mishandled. Do not recharge,
disassemble, heat, or incinerate.
Dispose of used batteries properly.
Bose Corporation hereby declares
that this product is in compliance
with the essential requirements
and other relevant provisions of
Directive 1999/5/EC and all other
applicable EU directive
requirements. The complete
declaration of conformity
can be found at:
Operate this product within the temperature
range of 5°F to 131°F (-15°C to 55°C) only.
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CONTENTS
ADVISORIES
1
Operational advisory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hearing safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
2
Volume control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Recognizing aircraft sounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Using audio sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Headset earcup requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Earcup inner screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
INTRODUCTION
4
What’s included . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
What’s in the carton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Control module variations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Power and cable variations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
PREPARING THE HEADSET FOR USE
8
The microphone assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
Attaching the microphone assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
The battery compartment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
Opening the battery compartment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
The operation switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Inserting and replacing the batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Connecting the headset to the aircraft . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Using the 6-pin plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Using the dual general aviation plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Using other plug types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
USING THE HEADSET
13
Wearing and adjusting the headset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Conditions related to fit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Microphone placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Clothing clips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Using the control module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Power button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Volume control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Power indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Auxiliary (AUX) audio input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Audio priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Using the headset with a Bluetooth®-enabled phone . . . . . . . . . . . . . . . . 19
Pairing the headset with your phone . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Bluetooth® volume control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Making and answering calls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
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CONTENTS
English
HEADSET CARE AND MAINTENANCE
23
Instructions for continued airworthiness . . . . . . . . . . . . . . . . . . . . . . . . . 23
Cleaning the headset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
General cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Headset earcup openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Microphone windscreen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Earcup inner screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Headband cushion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Replacing parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Microphone windscreen replacement . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Ear cushion replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Battery replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Headband cushion replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Microphone assembly or access cover replacement . . . . . . . . . . . . . . 26
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
TROUBLESHOOTING
27
In case of difficulty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
INSTALLATION
31
Mounting the aircraft panel connector . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Details on making the connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
TECHNICAL INFORMATION
34
36
SERVICE AND WARRANTY INFORMATION
Locating the headset serial number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Warranty period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Limited warranty service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
To return your headset to Bose for repair . . . . . . . . . . . . . . . . . . . . . . . 36
Contact information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Ordering parts and accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
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ADVISORIES
Operational advisory
The Bose® A20® Aviation Headset incorporates Acoustic Noise Cancelling®
technology. As with any complex electronic device, it is possible for this
headset to fail during operation. Symptoms of failure may include loud tones,
distortion, and loss of communications signal in the headset when used in the
Acoustic Noise Cancelling mode.
Note: The headset includes redundant circuitry to reduce the effects of such failures
and to allow for continued use of the headset in the passive noise reducing mode.
In passive noise reducing mode, the volume controls on the control module will
automatically be set to maximum volume. If additional volume control is
needed, you can use the intercom or radio volume control.
Acoustic Noise Cancelling mode is active when the headset control module is
powered on (power indicator is lit). The headset is in the passive mode when
the power is off (power indicator is not lit). See “Control module variations” on
page 6.
If your headset is aircraft powered, connect the headset to the aircraft power
sources only as described in “Connecting the headset to the aircraft” on
page 11. The headset will not operate properly if used with any battery source
other than the Bose A20 Aviation Headset control module.
Note: In the unlikely event of a headset issue, we suggest that you switch to an
alternate communications method and use standard cockpit resource
management skills to minimize distractions.
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ADVISORIES
English
Hearing safety
The headset is intended for use with the Acoustic Noise Cancelling® mode
turned on. Noise reduction and communications performance are reduced with
Acoustic Noise Cancellingmode turned off.
Volume control
Make sure your aircraft communications system volume control is easily
accessible. This control affects the strength of the communications signal
coming into the headset.
As pilot in command, you must be sure you can understand critical
communications even with Acoustic Noise Cancellingmode turned off. In this
case, you may need to turn up the aircraft communications system volume.
Avoid setting the volume controls at levels high enough to impair your hearing
during extended periods of headset use.
Recognizing aircraft sounds
With the headset’s active and passive noise reduction, typical aircraft sounds
(such as engines, propellers, warning alarms, and other sound sources) may
not sound familiar. We strongly advise you to make sure you can hear and
recognize these sounds when using the Bose® A20® Aviation Headset while
operating any aircraft.
Using audio sources
When listening to in-flight entertainment, or a portable audio source through a
Bose A20 Aviation Headset, be sure to limit the volume to safe levels that do
not interfere with your ability to hear informational sounds and warning alarms,
such as stall warnings or gear up, while piloting.
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ADVISORIES
Headset earcup requirements
Proper headset operation requires that the headset TriPort® openings on the
earcup are kept free of debris. The headset TriPort openings are located on the
outside of each earcup and include two holes and a screen.
TriPort
opening
Microphone
opening
Earcup inner screen
The protective inner screen is critical to the headset’s performance.
Earcup
inner screen
Do not attempt to remove, replace, or repair this screen. If screen replacement
seems necessary, contact Bose® Technical Support. See “Contact information”
on page 37.
If the screen gets wet or any foreign objects become lodged on or adjacent to
it, follow the instructions in “Headset Care and Maintenance” on page 23.
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English
INTRODUCTION
Congratulations on your purchase of a Bose® A20® Aviation Headset. The Bose
A20 Aviation Headset is our most advanced aviation headset yet. It delivers
significantly increased noise reduction and provides a more comfortable fit,
without compromising the clear audio you expect from Bose. Plus, it offers
auxiliary audio input and is available with Bluetooth® wireless technology.
What’s included
Each Bose A20 Aviation Headset is supplied with a control module, cable, and
carrying case. The type of control module and end-plug configuration depends
on the options you chose for your headset.
There are two options for the control module:
• Control module with Bluetooth wireless technology
• Conventional control module
There are several end-plug configurations for the headset. Your headset falls
into one of two general categories:
• Battery powered: Operates with battery power only.
• Dual powered: Operates with either aircraft or battery power. No battery
needed when connected to aircraft power.
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INTRODUCTION
What’s in the carton
Headset assembly:
Accessories:
Headphones
Carrying case
Clothing clip
2 AA alkaline
batteries*
Control module
See “Control module
variations” on page 6
for options.
3.5 mm adapter cable
Second clothing clip
Cable connector (varies)
Note: Cable connector types will vary based on model of headset. See “Power
and cable variations” on page 7.
Note: *Replace batteries with alkaline batteries only. Do not use any other battery
chemistries.
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INTRODUCTION
English
Control module variations
If you opted for Bluetooth® wireless technology, you received the control
module featuring Bluetooth technology. If not, you received the conventional
control module.
Bluetooth control module
Conventional control module
Left/Right volume controls*
Power indicator
Power button
Bluetooth
indicator
Bluetooth
function button
Bluetooth
Volume Up button
Multifunction
switch:
Audio Priority
switch:
Bluetooth
Volume Down button
Top
Intercom
prioritized
Top
Intercom
prioritized
Auxiliary (AUX)
audio input
Middle
Intercom
mixed
Middle
Intercom
mixed
Bottom
Intercom
only
Bottom
Intercom
only
*Control the intercom volume
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INTRODUCTION
Power and cable variations
The Bose® A20® Aviation Headset is available for purchase in different standard
aircraft connector options, including:
Battery powered options
Dual powered options
Operate with battery power only
Operate with either aircraft or battery power
No battery needed when connected to aircraft power
Dual G/A
U174
U384
6-pin*
5-pin XLR
8-pin
* An adapter is available from Bose to convert a 6-pin connector to a dual G/A or U174 plug
for additional connection flexibility. Other configurations require the purchase of a cable
assembly.
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PREPARING THE HEADSET FOR USE
The microphone assembly
Your headset may be shipped with the microphone assembly (boom microphone
and cable) attached to the left earcup. If your headset is shipped with the
microphone assembly packed separately, you can attach it to either earcup.
Attaching the microphone assembly
Choose the earcup (L or R) to receive the microphone assembly. Also, make
sure that the earcup connector pins are clean and free of debris.
1. Use a Phillips screwdriver to loosen the two screws on the terminator cover
near the bottom of the earcup where you want to attach the
microphone assembly.
2. Remove the terminator cover to reveal the connector pins on the earcup.
3. Carefully line up the microphone assembly to the small connector socket
on the earcup.
4. Slide the connector into the socket until it reaches the stop.
L for left
Connector
Terminator
pins
cover
Microphone assembly
Connector pins
CAUTION: Do not force the connector into the socket, or earcup damage may
occur.
5. Tighten the screws to secure the assembly.
6. Attach the terminator cover to the earcup that does not have the microphone
assembly attached. Insert the screws, then align and tighten them.
Note: The headset will not work without the terminator cover installed.
CAUTION: Be sure to try the headset and fully test its operation before flight.
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PREPARING THE HEADSET FOR USE
The battery compartment
The Bose® A20® Aviation Headset is shipped with factory-set operation defaults.
If you want to alter these defaults, you can change the operation switches
located inside the control module battery compartment. If you do not want to
change any of the operation switches, skip ahead to “Inserting and replacing
the batteries” on page 10.
Note: For aircraft-powered versions (5-pin XLR, 6-pin, 8-pin) batteries are not
required for operation.
Opening the battery compartment
You must open the battery compartment to access the operation switches.
Press down firmly on the battery compartment cover finger indent and slide the
cover down. The cover is tethered to the module. Do not attempt to detach it.
Note: The battery compartment cover is designed to remain securely closed. You
may need to use additional force when pressing down and releasing cover.
The operation switches
The operation switches control the Auto Off and Stereo/Mono functions.
Operation switches
To change the operation switches
1. Open the battery compartment.
2. If batteries are installed, remove them. In the battery compartment, you can
observe and change the switch positions.
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PREPARING THE HEADSET FOR USE
English
3. To change a switch position, use a pen or a small, flat-tipped screwdriver to
gently move the switch.
This table shows possible positions, default setting, and purpose for each switch.
Switch
Options
Purpose
1. Auto Off ON, OFF
function
Set at the factory to enable the Auto Off function. The headset
will turn off after 3 to 9 minutes of inactivity. To disable Auto
Off, set the switch to OFF. With the switch in OFF position, the
Acoustic Noise Cancelling® system will not turn off until you
press and hold the power button for at least one second.
Default: ON
2. Mono/
Stereo
Mono, Stereo
For most configurations, set at the factory for mono audio
systems (to provide audio in both ears). Set it to stereo (ST)
selection Default: MONO if your aircraft has a stereo intercom.
Auto Off functionality
The Auto Off feature detects when the headset is not in use and shuts it off after
several minutes to preserve battery power. The exact time it takes to shut off
varies and can range between 3 to 9 minutes after you stop using the headset.
When the headset is running on battery power only and is not plugged in to an
intercom, it will shut off even when there is an auxiliary input present.
If you are on a phone call and unplugged from an intercom, the headset will
allow you to complete your call, then it will turn off approximately three seconds
after the call is terminated.
Note: To use the headset when unplugged from the intercom to listen to auxiliary
input audio or as a Bluetooth® wireless technology-enabled headset to make or receive
calls, we recommend you disable the Auto Off feature for uninterrupted functionality.
Inserting and replacing the batteries
CAUTION: If the batteries do not fit correctly, do not force them in. Forcing an
improper connection will cause permanent damage to the control module.
To insert or replace the batteries
1. Turn off headset power.
2. Press down firmly on the battery compartment cover and slide the cover to
release. The battery door is tethered. Do not detach the door from module.
3. Insert the two supplied alkaline AA batteries into the control module,
observing proper polarity.
4. Replace the battery compartment cover.
Note: Replace batteries with alkaline batteries only. Do not use any other battery
chemistries.
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PREPARING THE HEADSET FOR USE
Connecting the headset to the aircraft
The Bose® A20® Aviation Headset can be configured to either plug into aircraft
power or rely entirely on battery power.
Using the 6-pin plug
A single 6-pin plug inserted into the 6-pin connector provides the headset with
aircraft power and intercom audio.
If your headset is aircraft-powered, a 6-pin connector must be installed and
mounted to an aircraft panel. See “Mounting the aircraft panel connector” on
page 31.
Note: An adapter is available from Bose to convert a 6-pin connector to a dual
G/A or U174 plug for additional connection flexibility.
To connect the headset
1. Align the 6-pin plug to the connector keyway by matching the narrow bar
on the plug to the slot on the connector.
2. Firmly press the plug into the connector jack.
Align keyway
Push plug in
To disconnect the headset
1. Pull back on the sleeve near the end of the 6-pin plug.
2. Gently continue pulling back to remove the plug from the connector.
CAUTION: Do not pull the connector out without first pulling back the sleeve.
Forcing the connector out will damage the cable and/or the aircraft instrument panel.
Pull sleeve back, then pull plug out
Sleeve
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PREPARING THE HEADSET FOR USE
English
Using the dual general aviation plugs
The most common battery powered (only) version of the headset has two
general aviation (G/A) plugs that connect to the aircraft audio. Although the
plugs look similar, the microphone plug is shorter, thinner, and has a slightly
different shape than the intercom plug.
Insert the thicker intercom plug in first. It will only fit into one of the jacks.
Then insert the thinner microphone plug into the other jack.
Microphone
Intercom/Audio
Using other plug types
The Bose® A20® Aviation Headset is also available with other types of plugs for
connecting to various aircraft audio jacks. These single-plug connectors should
be inserted into the appropriate jack on your aircraft control panel. Refer to
“Power and cable variations” on page 7.
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USING THE HEADSET
Wearing and adjusting the headset
Proper fit on your head is important both for comfort and optimal noise
reduction performance. Here are a few guidelines:
• Use the left (L) and right (R) markings above the earcups to orient the headset
properly.
R
L
• As you put the headset on, lightly grasp each earcup and adjust it so its
cushion is completely over your ear. You should feel an even, gentle pressure
all around each ear.
• Adjust the headband so it rests gently on top of your head.
Make your final adjustments with the headset powered on in a noisy
environment.
In very loud conditions, such as during takeoff, you may experience a brief
reduction in Acoustic Noise Cancelling® as the headset compensates for a
momentary pressure change. If the problem continues when the sound level
returns to normal, see “In case of difficulty” on page 27. If the problem persists,
contact Bose® Technical Support for assistance.
Conditions related to fit
A low rumbling sound or frequent, brief losses of Acoustic Noise Cancelling
noise reduction may indicate an improper fit or blocked earcup ports. See
“Headset earcup openings” on page 23 for instructions on removing
blockages.
During a long flight, you may feel a slight pressure point, which can be relieved
by adjusting the headband position. Your experience with using the headset will
help establish a sense of how it should sound and feel.
Microphone placement
Microphone placement is important for clear communications. With the
headset on your head, make these adjustments:
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