FaceTime Audio works over cellular data
I have read many times on iOS 7 reviews that FaceTime Audio only works if you're connected to Wi-Fi. But, I have just called my iPad from my iPhone,* with the latter connected to an EDGE network (and Wi-Fi disabled), and it worked just like it does over Wi-Fi. I might try calling someone else later, but I don't see how that can be different.
It might help that my carrier allows tethering and regular FaceTime over cellular, but I thought this was a different beast altogether.
Have you guys to tried this? What has been your experience so far?
* Yes, with iOS 7 you can finally FaceTime yourself if you have two or more iOS devices and are really really lonely.