User Manual
Table Of Contents
- About your Bose® A20® Aviation Headset
- Components
- Preparing the Headset for Use11
- The battery compartment
- Connecting the headset to the aircraft
- Wearing and adjusting the headset
- Using the control module
- Primary and secondary audio sources
- AUX audio sources (wired)
- Bluetooth® audio sources (wireless)
- Using the headset with a Bluetooth® device
- Pairing the first device
- Pairing another device
- Switching between connected devices
- Bluetooth multi-function button
- Making and answering calls
- Reconnecting to a previously connected device
- Recovering a lost connection
- Disconnecting a Bluetooth device
- Clearing the headset pairing list
- Controlling Bluetooth volume
- Using the headset with a Bluetooth® device
- Secondary audio modes
- Cleaning the headset
- Instructions for continued airworthiness
- Managing multiple secondary sources
- Ordering parts and accessories
- Contact information
- Limited warranty
- Locating the headset serial number
- Mounting the aircraft panel connector
- Replacing parts
- Microphone windscreen

Troubleshooting
34 - English
AUX audio source
Problem What to do
No audio from
AUX source
• On the AUX source, turn the volume up.
• Make sure the 3.5 mm AUX audio cable is firmly connected to the
control module and the AUX source.
• On the control module, make sure the Secondary Audio Mode
selector is in the MUTE or MIX position.
• If the Secondary Audio Mode selector is set to MUTE, all
secondary audio sources are temporarily muted when an intercom
signal is detected. Secondary audio will return after intercom audio
ceases.
• If you are on an active Bluetooth phone call, you will not hear audio
from the AUX source. AUX audio will resume after the phone call
ends.
• Try another AUX source.
Audio in one ear
only from the
AUX source
• Make sure the 3.5 mm AUX audio cable is firmly connected to the
control module and the AUX source.
• On the headset, make sure the terminator cover is in place and
properly connected. Refer to “Attaching the microphone assembly”
on page 11.
Cannot hear
intercom com-
munications while
listening to audio
from AUX source
• Make sure the headset is firmly connected to the intercom/radio
system.
• Make sure the 3.5 mm AUX audio cable is firmly connected to the
control module and the AUX source.
AUX source does
not mute with
incoming intercom
communications
• Inside battery compartment, check the Priority (BT-AUX) switch.
See “Operation Switch” on page 13.
• If the Secondary Audio Mode selector is set to MIX, all secondary
audio sources are heard as mixed with the intercom audio. To mute
the AUX source, set the switch to MUTE or OFF.
Cannot be heard
on a phone call
• The headset does not support microphone operation when con-
nected to a device via the AUX audio cable. Hold the device closer
to your mouth to use the device’s mic. Or, try connecting the
phone via a Bluetooth connection.