If the sound during call is too low to be recognized, please try the following.
- Increase the volume of the device while calling.
Note: If you do that while you aren't calling, the volume of notification sounds will be changed.
- If it is still too low to be recognized, please try the following.
- Turn on the "Volume Up" button while calling.
Note: The sound quality becomes somewhat inferior.
- Turn off the "Noise Cancel" button while calling.
- Turn on the "Volume Up" button while calling.
Note: The volume depends on the device the other person is using and sometimes he/she will sound quiet.