Straight from the horse's mouth. New At&t iPhone page

ColsTiger

Zealot
Gold
Mar 8, 2007
5,856
2
38
Columbus, GA
Is it the entire ss or just the last 4? Also What would happen if the BDAY didn't match that of the account holder? DO you think you would receive an error if you were already a customer?
You'll need the entire SS# to activate the phone. You can watch it in the demo.