Using an AT&T phone on T-Mobiles network

[SimbaNala]

So I'm looking to get the Torch 9810, and was wondering. Seeing as T-Mobile and AT&T had this one, if I were to get an unlocked AT&T one, would I be able to fully use it on T-mobiles network or would some features not work between the networks.

Basically, can I look into getting a unlocked phone or should I stick to getting just a plain T-Mobile locked phone. Thanks for any insight!!

[californiablackberry]

It'll work, but you won't get 3G, only EDGE.
It's best just to get a T-Mobile branded device.

[SimbaNala]

What if it's a 4G phone? the 4G won't work?

[californiablackberry]

Originally Posted by SimbaNala

What if it's a 4G phone? the 4G won't work?

No, you won't get 3G or 4G, only get EDGE.

[SimbaNala]

Okay, thank you. So then what if I get one that is unlocked and has not been used with any carrier (not an At&T or T-Mobile phone) but one right from RIM themselves? Would that have the same issue?

[redk]

If you want the 3G to work with tmobile you have to make sure the phone supports bands 1700 and 2100 for hspda.

[HofstraJet]

It isn't an issue of whether the phone has been activated on anyone's network - the issue is whether the phone has antennas that receive the T-Mobile 3G/4G bands since AT&T and T-Mobile operate on different frequencies.

[chrischoi]

T-Mobile Frequencies

850 MHz GSM/GPRS/EDGE 2G n/a 1996 Not operated by T-Mobile. Competitor networks accessible via roaming agreements
1900 MHz GSM/GPRS/EDGE 2G 1994 1996 Based on original VoiceStream Wireless GSM PCS network
1700 MHz UMTS (W-CDMA)/HSPA/HSPA+ 4G (formerly 3G[34]) 2006 2008 (3G), 2010 (Marketed as 4G) First carrier in the U.S. to deploy services on AWS frequencies. Markets HSPA+ as "4G". UMTS frequency bands IV
1900 MHz UMTS (W-CDMA)/HSPA/HSPA+ 4G 1994 2011 According to reports from users, T-Mobile started to use PCS for UMTS in some areas.[35] UMTS frequency bands II

ATT Frequencies

850 MHz GSM/GPRS/EDGE 2G
1900 MHz GSM/GPRS/EDGE 2G
850 MHz UMTS/HSPA 3G
1900 MHz UMTS/HSPA 3G
700 MHz LTE 4G

The only thing that matches up on the ATT Phone and T-Mobile Network.

850 MHz GSM/GPRS/EDGE 2G
1900 MHz GSM/GPRS/EDGE 2G

Best way to explain it is like a CD and DVD. Just because you can put it in, doesn't mean it can read/support it.

[blackberry-unlocking710]

Mostly,
Unlocked At&t Blackberry will work with Blackberry device from Rogers / Bell.
Unlocked T-mobile Blackberry will work with WIND / Mobilicity Blackberry devices.
If you use At&t with T-mobile or Rogers with WIND you will get only 2G speeds.
It's all related to the bands used by the carrier for fast connections.

[SimbaNala]

Thanks for all the input. I ended up with a T-Mobile one after all, they allowed me to upgrade early