[Beckaalou]

my blackberry 8520 wont take any other sim. i want to change my number but keep the same phone. the network on both of the sims are the same but it will load perfectly with one sim but freezes on the t-mobile screen when i put the other one in. i havent got a clue as to why this is happening but im hoping someone on here will. please help

[Dubdub]

Both SIMS are from T-Mobile?

[tsac]

I bet no.

Go to the top of the Forum page and go to the Unlock service.

Also read the FAQ on a locked BB.

[mobileunlocked]

Before you go online to unlock your BlackBerry, it's best to check that your phone is in fact locked.

Although seeing whether a SIM card works or not is the normal way, the most accurate way is to:

Go to Menu > Options > Device > Advanced System Settings > SIM Card
Type MEPD
See if one of the lock types on the list that appears is Active.

If one or more is active, then you do need to order BlackBerry unlock codes.