With help from Roamer1, I now understand what is going on with the new SHARED banner on my AT&T TDMA phone. I can see that using a private network to change the banner when you are in your home area is a convenience for customers. My phone is old enough that I’m guessing it was probably not programmed with a private network when I got it and AT&T programmed it when I changed plans. So how does over-the-air (OTA) programming work? An out-of -band channel, part of the control mechanism, a secret code in SMS? Do I need to read the specs or does someone know the answers? Have there been mistakes in OTA programming? How is the security? Is it possible that hackers might be able to reset everyone’s phones?