Hi! AT&T GSM Wireless (S46 Multiband Phone Only). When screen says AT&T Wireless your phone is in GSM. When your screen says AT&T you are receiving TDMA.
You can test this by clicking on menu then 8315, this will bring you to User settings. select tdma only, select. WAIT, may take a few seconds. Screen will now say AT&T. To return to GSM, push the top left side button once "user Settings" now reselect Automatic/ select screen will return WAIT a few seconds may take a couple of goes just wait. Screen will return to AT&T Wireless.
Reg. Frank R