No notification sound for face time

Did you check the usual suspects?

1. Do you have your ringtone volume up?

2. Make sure the device isn't muted. See here: http://support.apple.com/kb/ht4085

3. Make sure Do Not Disturb is off. Swipe up from the bottom if th screen to access Control Center and make sure the moon icon is not lit.

4. Make sure the sound you set for your FaceTime Alert Sound is something that is loud enough for you to clearly hear. Tapping the sound will give you a preview.

What do you mean by the sound setting?

FaceTime is not in the Sounds settings.

To set a FaceTime Alert Sound go here:
Settings > Notification Center > FaceTime > Alert Sound

You're welcome.

try switching the button on the right of the ipad/ipod/iphone. (when in stand mode)

had the same problem on my ipad air 2 , the mute softkey button was on. It pops up on the menu when you swipe from the bottom of the screen upwards. Deselected the mute button and then the facetime began to ring for incoming calls.