Purchase US GSM phone for use in Germany?

[dg7feq]

Originally Posted by djinks

I thought I might like to have a mobile phone for my next trip to Northern Germany. I'm confused by the different frequencies, when each is needed etc. I will most likely purchase a Tschibo SIM when I arrive and I can see two scenarios for use of the phone:

1 - a little voice, but mostly a monthly 5GB data pack that I can share with my O2 surfstick and laptop
2 - Use VOIP and no voice minutes on the Tschibo SIM, swapping the SIM to the surfstick for laptop sessions

Being confused about the radio frequencies, here is my question:
What would be the limitations of these above approaches if I brought an unlocked (US) T-mobile 4G with me. Would an AT&T phone be better? I mention them because I can pick one up easily at a moderate price on Craigslist.org. My initial research suggests the 2100 frequency is common with the O2 and (US) T-mobile phones, but I have also read that other frequency ranges will also be necessary for higher data speeds (~3.5mbps).

Looking at the charts on this page, it appears that both ATT and T-mobile US phones are missing one of the two frequency ranges required for high-speed data in Europe. AM I right?

you need 3G 2100 MHz for high speed data usage and 900/1800 MHz for 2G (voice/EDGE) coverage. If you only have 3G you will have many network gaps.

Chris