How can I make an audio-only FaceTime call?
FaceTime gives iOS users the ability to video chat, but did you know that FaceTime can also be used to make audio-only calls? As long as both call participants have FaceTime the iPhone can make a normal phone call using the service.
Contacts with FaceTime capability will have both a video icon and phone handset icon in their contact information.
To make a FaceTime audio call tap the phone handset icon on the right.