Nokia 9 - Manual (Page 52)

For the best noise cancellation, hold the phone with the earpiece to your ear and the
main microphone towards your mouth. Do not cover the secondary microphone next
to the camera flash.
If you want to let the person at the other end of the line also hear the background
noise, for example, the music when you're at a concert, you can temporarily
deactivate noise cancellation.
Activate or deactivate noise cancellation
Select and
Device > Call , and activate or deactivate Noise cancellation .
Answer a waiting call
You can answer a call when you have another call in progress. Call waiting is a network
service.
Select the waiting call and . The first call is put on hold.
Activate, deactivate, or check the status of the service
Select and
Device > Call , and activate or deactivate Call waiting .
Swap between an active call and a call on hold
Select the call.
Connect the call on hold to the active call to start a conference call
Select
Conference call .
End an active call
Select .
End both calls
Select >
End all calls .
Recent calls
Your call history is stored on your phone.
52 Calls