I have the unlimited BB plan and have never received a separate charge for using the tethered solution. I ran a query on the modem and there are a few places that error out. I am confident that Cingular has this blocked. I took the sim out of the 8700 and put it back in the 7100g and it connected to the network like a charm. I ran a query on the 7100g and it reported back with all successful at commands.