Bose A20 User Manual

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Auxiliary (AUX) audio input

The Bose® A20® Aviation Headset provides a1/8 inch (3.5 mm) AUX audio input that allows you to use your headset with an external audio source such as a portable GPS or a portable audio device. The connector is located at the bottom end of the control module as shown.

AUX audio input

Your headset includes a 1/8 inch (3.5 mm) adapter cable to connect your external audio device. Plug one end of the adapter cable into the headphone plug on your device and the opposite end into the headset AUX audio input.

Note: None of the functions of a connected audio source are controlled by the control module.

Note: This feature will not work unless the multifunction switch is turned on.

Note: When the headset is running on battery power only, and it is not plugged into an intercom, it will shut off even when there is an auxiliary audio input signal present. To use the headset when unplugged from the intercom to listen to auxiliary input audio or as aBluetooth® wireless technology headset to make or receive calls, we recommend you disable the Auto Off feature for uninterrupted functionality.

Audio priority

The Bose A20 Aviation Headset allows you to decide the priority of the audio sources you want to hear while using the headset. On the Bluetooth control module, the audio priority is controlled by the multifunction switch. On the conventional control module, the audio priority is controlled by the audio priority switch.



Multifunction/Audio priority switch

The multifunction/audio priority switch has three positions:








Intercom prioritized

When the switch is in the top position and an


over AUX

intercom signal is detected, AUX audio is muted.


Intercom mixed with

When the switch is in the middle position and an



intercom signal is detected, AUX audio is mixed



with the intercom audio.


Intercom only

When the switch is in the bottom position, only



intercom audio is active.

Note: On theBluetooth® control module, when aBluetooth wireless technology call is present, the audio from the call mutes the signal on the AUX audio input. In either the top or middle position of the multifunction switch, both the intercom and theBluetooth wireless technology signal are heard as mixed.



Using the headset

with a Bluetooth®-enabledphone

Pairing the headset with your phone

Pairing entails having the Bose A20® Aviation Headset in pairing mode, setting yourBluetooth-enabled phone to “discover” the headset, then confirming the connection on the phone. Before you use your Bose® A20 Aviation Headset with your mobile phone, you must pair the two devices.

1.Turn on the headset and make sure the multifunction switch is in the top or middle position, NOT in the emergency off position.


Multifunction Switch

indicator light


Power button










Top position

Middle position


The power indicator light glows green or yellow, depending on the charge level of the battery. If the light is red, the battery is low and needs replacing.

2. Press theBluetooth function button (to activateBluetooth.


If this is the first time you’ve activated or are attempting


to pair Bluetooth, theBluetooth indicator will flash at a


slow rate alternating with the Power indicator. This


indicates that the headset is in “discoverable” mode


and ready to be paired to a cell phone.


If the Bluetooth indicator does not flash alternately with the Power indicator flash or you are trying to pair a headset that has previously been paired with another phone, you will need to press and hold theBluetooth function button for 5 seconds in order to put the headset into “discoverable” mode.

3.With your Bluetooth-enabledphone turned on, locate the Bluetooth feature, usually under Tools, Connect, orBluetooth Devices. (Refer to the owner’s instructions that came with your phone for further details.)

4.Set the phone to “discover” or “add” a Bluetooth device. When Bose A20 appears in the list of devices, select and confirm this choice.

5.If you are asked for a passkey or PIN, enter the digits 0000.

The control module Bluetooth and power indicators flash together to confirm successful pairing.

If pairing is unsuccessful, repeat steps 3 - 5 above.



Note: The Bose A20® Aviation Headset will automatically exit pairing mode after five minutes of inactivity.

Bluetooth® indicator light status

The Bluetooth indicator is a blue light on the control module. It shows the status ofBluetooth functions, as follows:





Flashes slowly, alternating with the power indicator.

Headset is discoverable or is pairing.



Flashes twice quickly with each power indicator

Bluetooth technology is ON but not


connected to a phone.



Flashes at the same rate with the power indicator

Bluetooth technology is ONand

(green or amber).

connected to phone.



Flashes once quickly with each power indicator flash.

Headset is in an active phone call.



No light

Bluetooth technology is not enabled.



Reconnecting to a previously connected phone

To reconnect the headset to a previously connected phone or other Bluetooth wireless technology device, briefly press theBluetooth function button on the headset control module.

The headset control module attempts to connect with the last connected Bluetooth wireless technology device.

Note: The Bose® A20® Aviation Headset can only be connected to oneBluetooth wireless technology device at a time. If you press theBluetooth function button on the headset control module for more than five seconds, the currently connectedBluetooth wireless technology device is disconnected and the control module enters pairing mode.

Recovering a lost connection

When a connected Bluetooth wireless technology device moves out of range and the connection is lost, the Bose A20 Aviation Headset automatically attempts to reconnect. If a connection still does not exist after five minutes, theBluetooth wireless technology receiver in the control module remains on, but not connected. TheBluetooth indicator on the Bose A20 Aviation Headset control module will exhibit a fast double flash initiated at each power indicator flash.

Disconnecting a Bluetooth technology-enabledphone

If you use a connected phone to end a Bluetooth wireless technology connection, theBluetooth technology receiver in the headset control module remains on, but no longer attempts to connect. ABluetooth wireless technology connection is ended by turning the phone off, ending the current call, or discontinuing the wireless connection.



If you turn the headset control module off, the control module Bluetooth wireless technology receiver also turns off, ending the connection to theBluetooth technology-enabledphone.

Bluetooth® volume control

The Bluetooth volume control increases or decreases the volume of the mobile phone that is paired to the Bose® A20® Aviation Headset. TheBluetooth volume control is located on the right side of the control module. You can only adjust theBluetooth technology volume during an active phone call. To change the volume, press the volume up or volume down button.

volume down volume up

Each time you press a Bluetooth volume button, the volume increases or decreases one level.

Note: Pressing and holding the volume button changes the volume continuously.

Note: WhenBluetooth wireless technology is active, you cannot mute the sound using theBluetooth volume buttons.

To clear pairing device history from the headset

With Bluetooth technology enabled and on (Bluetooth indicator light flashing) while not on a call, press and hold bothBluetooth volume up andBluetooth volume down buttons at the same time for 8 seconds. After 8 seconds, cycle theBluetooth power using the multifunction switch.



Making and answering calls

To make a call

Dial from your mobile phone, and the call will automatically transfer to the headset. If your phone has voice-activateddialing, press theBluetooth® function button and wait for the phone voice prompts.

To activate voice dialing (if your phone provides this feature)

When there are no active or incoming calls, briefly press the Bluetooth function button.

To answer a call

Briefly press the Bluetooth function button. You should hear a short beep in the headphones before you hear the incoming call.

To end a call

Briefly press the Bluetooth function button. You should hear two short beeps in the headphones to indicate that the call has been ended.

To reject an incoming call

Press the Bluetooth function button for three seconds.

Note: To avoid putting the control module into pairing mode, do not press theBluetooth function button for more than five seconds.

To redial the last number

When there are no active or incoming calls, press the Bluetooth function button twice in quick succession.

Note: Whether or not you can reject an incoming call, activate voice dialing, or redial the last number, depends on the capabilities of your phone. Please check your phone user guide for further details.

To transfer the audio to the mobile phone

When you are on a call, press the Bluetooth function button for three to four seconds. This transfers the audio to the mobile phone handset while theBluetooth wireless technology connection remains active.

Note: If you are on a 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. To use the headset when unplugged from the intercom to listen to auxiliary input audio, or as a standaloneBluetooth technology headset to make or receive calls, we recommend you disable the Auto Off feature for uninterrupted functionality.



Instructions for continued airworthiness

Bose recommends following the general care and maintenance instructions in this guide. With normal use, items such as windscreens and ear cushions may require periodic replacement. If cleaning or replacement of these items is needed, follow the recommendations on the following pages. All other care and maintenance, in and out of the warranty period, must be performed by Bose or an authorized repair facility.

CAUTION: Do not immerse the headset in water or any other liquid. If the headset is immersed in liquid, do not use it. Contact Bose® Technical Support for assistance.

Cleaning the headset

General cleaning

Gently wipe the outside surfaces of the headband, connectors, plastic parts, and headband cushion, using a soft cloth moistened with water and mild soap. Take special care when cleaning the ear cushions and the outside surfaces of the earcups. Do not immerse ear cushions in water or any other liquid.

Headset earcup openings

The TriPort® headset opening and the microphone opening must remain clean and free of debris. Check to ensure that the openings on each earcup are clean before each flight.

TriPort headset opening



When wiping down the headset earcups, be sure not to force any dirt or debris into the openings. Carefully use tweezers, if necessary, to remove foreign matter that may be lodged in the openings. Do not blow air into or vacuum the openings as this may damage the headset.



Microphone windscreen

Remove the windscreen from the microphone as described in “Microphone windscreen replacement,” below.

Rinse and air dry the windscreen. Make sure the windscreen is completely dry, then reattach.

Earcup inner screen

Do not attempt to remove, replace, repair, or clean this component. Located inside the earcup, the inner screen is critical to proper headset operation. If the screen appears to be damaged or worn out, contact Bose.

If the inner screen becomes damp from environmental moisture such as light rain, dew, perspiration, or condensation, allow it to air dry only. Do not use electric heaters, blowers, or hairdryer-typedevices to dry the inner screen.

Headband cushion

1.Remove the cushion as described in “Headband cushion replacement” on page 26.

2.Place the cushion in a solution of water and a mild detergent.

3.Allow the cushion to air dry, then reattach.

Replacing parts

Through normal use, parts like windscreens and ear cushions may require periodic replacement. Replacement parts can be ordered directly from Bose Corporation. Please refer to “Contact information” on page 37.

Microphone windscreen replacement

1.Roll the band that secures the windscreen off the tip of the microphone and dispose of it.

2.Gently slide the windscreen off the microphone.

3.Slide the replacement windscreen on and make sure it fits completely over the microphone.

4.Roll the new band onto the microphone tip, to about 1/4 inch from the end of the windscreen, to secure it.



Ear cushion replacement

As a general rule, ear cushions should be replaced every six months or every 350 hours of use, depending on how often you fly. You may have to replace them more often, if you:

Have a full beard or heavy whiskers.

Subject the headsets to severe temperature extremes such as parking your airplane outside in severe cold or heat.

Put excess strain on the cushions because of improper storage.

Indications that the ear cushions need replacing include:

Flaking of the outer covering.

Cuts or tears.

Flattening of the cushion, reducing the effectiveness of the seal.

To extend the life of the ear cushions, perform regular cleaning as described in “General cleaning” on page 23.

Replacing the ear cushions

1.Grasp the ear cushion skirt where it folds into the slot on the earcup.

2.Gently pull the ear cushion skirt up and away from the earcup.

3.Properly align the replacement ear cushion with the earcup.

4.Tuck an edge of the ear cushion skirt into the slot behind the ear cushion flange. Be careful not to fold the skirt over.

5.Gently stretch the cushion around the earcup, working the skirt into the slot as you go.

6.Grasp the ear cushion and adjust its position to remove any folds in the skirt and wrinkles in the cushion.

Battery replacement

Refer to “Inserting and replacing the batteries” on page 10.



Headband cushion replacement

The headband cushion is designed to give the maximum level of comfort to your headset.

Bose recommends that you replace the cushion after regular care and maintenance fails to restore the wool pile to its original size and shape.

To replace the cushion:

1.On a protected surface, turn the headset upside down. Remove the old cushion from the headband.

2.While still holding the headband open, align the center of the new cushion with the center of the headband and press firmly from the center toward the outside.

Headband cushion

Microphone assembly or access cover replacement

Replace the microphone assembly or connector access cover as described in “Attaching the microphone assembly” on page 8.


Store the headset in a ventilated area away from direct sunlight. Remove the batteries before storing the headset for extended periods.