Does T-Mobile lock phones?

[Shadow Conception]

My mom just brought over a phone from Bangladesh. It has a GrameenPhone SIM inside it. She wants to stick a T-Mobile SIM inside it so she can use it here.

However, when we go back to Bangladesh (next year), can we just take the SIM out and stick in the GrameenPhone SIM without hassle?

In other words, does T-Mobile lock their phones when you sign up for them with an unlocked phone?

 

[bruceb]

Easiest way to tell is try a T-Mobile or any other carrier (AT&T) SIM card in it and see if it says Locked or not. If not, then you are good to go.
Since you got it overseas, except for maybe changing some options, such as band (we uese GSM Quad Band) it should be unlocked already.
If you bought a new phone here in the US from any carrier, it would be locked to their network.

 

[Shadow Conception]

It's a tri-band (900, 1800, 1900), which means it's great for int'l use, but only alright for NA-use. It is unlocked already. I just need to know whether T-Mobile will lock it when I stick its SIM in. And if they'll revoke the lock if I ask them to.

 

[pm]

No, T-Mobile won't lock it. In fact, I'm fairly certain that - since SIM card information is accessed as data not as code - it's not feasible to have a SIM card lock a phone.

In addition, T-Mobile will unlock phones which you purchased from T-Mobile that are locked after a ~3 month period. So even if it was possible to lock a phone through a SIM (which it's not), and even if T-Mobile were locking phones on their system (which they don't), you could ask them to undo it and they would.

 

[Shadow Conception]

Alright, thanks a bunch guys!

 

[Shadow Conception]

Instead of starting a new thread, I'll bump for another question.

Any catches I should be aware of before going with T-Mobile Pay As You Go?