No sound with iSight in Face Time

anyone have any idea about this? please if anyone has any idea about this than please provide me. I have tried to use my iSight with Face Time but i cant be able to do this. so, if anyone has any idea about this than please help me.

I want to use an external iSight camera, to "face Timing" too. I have the iSight connected to my Mac Mini 2009th. The camera is fully recognized. This left me full of anticipation run FaceTime, but there is no sound recorded. Compared to me, but there is absolutely no sound at his door!

I searched the forum but found nothing. The new macbook came out with a camera instead of the Facetime iSight. technically, what difference? because in the technical characteristics of Apple, no drill. Also, what are the benefits of applying Facetime over iChat? only being able to communicate with an iPhone? is it compatible with iChat?

If I do not talk nonsense only appelation exchange iSight and FaceTime. Compared to iChat is not the same. FaceTime uses its own protocol and can only communicate with users from Facetime.

So it mean another chat software and more. me trying to reduce the number. for example on the MBA, they say, only FaceTime Camera, Is this an oversight or til there a difference?