What happens when I unlock my cell/mobile phone?

[Jinx007]

I am currently on the network Orange and I want to keep the phone I have now and switch to T-Mobile, I have been told I have to unlock my phone.When I do unlock it I have been told I will be able to use a T-Mobile sim card in my phone, but will I lose anything on my phone? I have a lot of music and pictures that I don't want to lose.

 

[jong85]

Your music and pictures won't be lost, your phone will simply be able to access other networks. You can still access your data when you're using T-Mobile's network.

 

[habeeb24]

On your music & pictures are you saved in memory card & phone memory? if you saved all in memory card, you can save everything.. Remove the memory card from the cell phone and format the mobile..