Bose A20 Aviation Owner's guide - Page 5

English Tab 2, 10 Tab 3, 11 Tab 4, 12 Tab 5, 13 Tab 6, 14 Tab 7, 15 Tab 8, 16 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. 1