HTC Desire HD unlocked, cannot connect to 3G I recently bought an unlocked AT&amp;T HTC Desire HD from an E-bay seller in India.
I'm using a Tata Docomo Sim on the device. Although having subscribed to 3G data, I am not able to use it. Can anyone help me with how I can configure and use 3G with my mobile?

I tried all the APN settings available online, of which none worked. I am able to just use the EDGE (2G) network, which is too slow. Hope someone helps me to connect 3G on HTC Desire HD for Tata DoCoMo India. 

Regards,
Praveen
AT&amp;T uses 3G frequency bands 850 MHz and 1900 MHz.  From what I can tell from the phones they sell, Tata Docomo uses the 900 MHz and 2100 MHz 3G bands.  They're not intercompatible.  Most often when you buy a US phone for use outside the country you'll want the T-Mobile version. Or a quad-band or 5-band phone which would eliminate the problem altogether.