A:AnswerIf i understand your question correctly, you can use this with an existing SIM card, however if that card was purchased before 5G was available, then you will have be able to access the 5G network!
A:AnswerThe unlimited plan for AT&T is only needed if doing the trade in promotion. However, (you would get $350 on trade in over 36 months for the 6s right now though) The $200 off the phone is also done over 36 months, but does not require the unlimited. They are trying to keep you on for as long as they can so they spread the discount over 3 years.
