 
■ Active noise cancellation
Active noise cancellation reduces ambient noise in noisy environments. 
You can also use active noise cancellation for noise reduction, for 
example, on an airplane when Bluetooth connectivity is deactivated and 
the CA-143U or CA-182U audio cable is not connected to the headset.
To activate active noise cancellation, slide the power key for active noise 
cancellation toward the charger connector. The indicator light for 
charging and active noise cancellation is displayed green.
To deactivate active noise cancellation, slide the power key away from 
the charger connector. The indicator light for charging and active noise 
cancellation turns off.