If this is happening on multiple phones, follow this link for instructions
You are having trouble with hearing the person on the other side of a call or they are having trouble hearing you.
Mute
button is not lit up. If it is, press it to deactivate muting and try again.Headset
button is not lit up. If it is, press it to deactivate the headset jack.X
key, located under the arrow keys, until you see a message on the screen asking if you would like to reboot. Press OK
and the phone will reboot. Make another test call. If this doesn't fix this, reply to the original ticket or call 919-268-4900.