said by Paralel:Well, it's pretty hard to look into. You won't find this information on an AT&T web page. The Sales department doesn't know. Tech Support won't know what you're talking about. People in public forums will give you conflicting and untrustworthy information. A lot of time, all you can do is sign up and reverse engineer the product.
If this is so important, why people don't look into this before switching is beyond me.