Originally Posted by Tadaen Sylvermane
If you get a phone from AT&T and are able to get it unlocked, you can use on T-Mobile but will only get Edge (slow speed).
I hate to derail but does this explain mine as well. iphone 4 originally got on ATT, recently unlocked and switched to tmobile. Never get 3g only edge i guess its called. Its just a E on the top where it used to say 3g all the time. Only happened since changed to tmobile.
Your phone does not have the 2nd frequency band required to work on Tmo's HSDPA+ network.. so 1900mhz GSM EDGE [which is really really slow.. slower than 3G substantially] is the only operating frequency you can grab of Tmo's.
*If you start with ATT.. and go TMO.. you need the following to have full speed 3/4G with Tmo:
*If you start with Tmo and go ATT.. you need the following to have full speed 3G/4G [no LTE though]:
ATT uses bands independently .. this means you can Tx/Rx from the same band. Tmo.. uses separated uplink and downlink.. so you have; Tx on 800.. and Rx on 2100 [or vice versa]. This is why without BOTH bands.. your phone will NEVER get 3G reception from Tmo.. only GSM EDGE [1MB].