850 900 band
If your provider is Cingular, you will not have service in all locations indicated on the Cingular coverage map because some areas are exclusively 850 MHz signals. You might be able to roam to other GSM providers that are transmitting in the 1900 MHz band depending on Cingular's roaming agreements.
However, if you are a T-mobile customer (1st of all, your question is in the wrong forum), you will not have any issue with T-mobile towers; they all transmit in the 1900 MHz band. You will notice that T-mobile recently changed their coverage map to indicate where 850 MHz roaming is available. This would not be available to you with your current device.
You are correct about the 900 MHz not being in use in the US. Th...
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