Motorola MC55 - Enterprise Digital Assistant, Руководство пользователя, Страница: 207 / 245

B - 4 MC55 User Guide
• Only the Avaya softphone is currently supported.
Acoustic Echo Cancellation
Acoustic Echo occurs during a voice call when the audio from the earpiece enters the microphone of the same
device. This results in the person at the other end hearing back a delayed version of his/her own voice (“Echo”).
Needless to say, “Echo” is not desirable, and needs to be suppressed. This is the functionality performed by the
Acoustic Echo Canceller (AEC). There are two approaches to suppressing the Echo:
• Turn the Acoustic Echo Canceller (AEC) on permanently. This approach is not very efficient because the
device consumes more power when the AEC is on.
• Turn the Acoustic Echo Canceller (AEC) on only when there is an ongoing call.
VQM follows the second of the two approaches mentioned above.
VQM automatically turns on the Acoustic Echo Canceller (AEC) when the mobile device is in a VoWiFi call. When
the call is terminated, VQM turns the AEC off. Note that the AEC is turned on for speakerphone and handset
modes and does not get turned on for Bluetooth headset mode. Bluetooth headsets typically have an Echo
Canceller built in. Turning the AEC on only while on a call saves battery power, compared to leaving the AEC
turned on permanently.
The AEC is not turned on for Cellular calls because the WWAN phone application has a built-in echo canceller.
Disabling VQM
To disable VQM perform a warm boot.