Hi. I bought it used.
This is a discussion on How can i tell if I have the T-Mobile or AT&T Nexus One ? within the Nexus One forums, part of the Google Phones category; Hi. I bought it used....
Hi. I bought it used.
I had the same question. What I did is go to the AT&T Store, and got a pre-paid service for it. It cost me $40 for 500 MB and 150 talking minutes. Bring your phone and they can also check it with an activated SIM before you buy. Keep in mind that the best you will get is edge service. A bit slow, but it does work.
I did not go to the T-Mobile store, but I would imagine that they could do the same.
Pull the battery, and look at the serial number, if it ends with 9100 it's T-Mo, if it ends with 9110, it's AT&T...
I have a AT&T Nexus One and the end of the serial number is not 9110.
I think the number you want to look at is the IC number.
The last four digits of my IC number are 9110.
The number is listed right after the FCC ID which is above the line that reads "Use only batteries and power supplies listed in user manual".