reply to brg
Re: Use current ATT Modem for Uverse & avoid New Modem charge? As long as the modem purchased was legally sold to you, and not done in violation of AT&T service agreements, I don't see why it would be a problem. Although, this is AT&T we are talking about, logic is not necessarily applicable in the reality which they occupy.
Yup: Totally legit/authentic/current modem.
The question really boils down to "can you avoid being required to purchase what would be an unnecessary modem/can you avoid having to pay that unnecessary $100."
@Thinkdiff's experience is option 2. While not as user friendly (and way more cumbersome for both parties) as this rare instance of BYOD/no charge, it is an acceptable alternative.
If it actually works that way...