computer is not recognizing iphone

I bought 2 iphone 4's from a friend. I fixed the screens and am trying to give them to other friends. Only problem is that neither of them will connect to my Macbook (itunes) they are not registering at all. I don't know if it has anything to do with the fact that there is no service on the devices. I thought the problem was the charger connector so I changed that out as well. Still, it will not connect. Has anyone else had this issue and know what I can do to fix it.

I have the newest itunes and iphone software. I have used multiple USS connectors as well.