The Nokia 1600 should be an easy phone to unlock for free. Do not try to do this yourself through on-line Nokia calculators. Follow the steps below and your phone should be sim free by this evening
Go to
UnlockMe - Unlock Nokia - Free Unlocking Advice & Tutorials
Click on the forum link to the left
Create an account (its free)
Go to the forum listed GSM unlocking
Create a post asking to have your Nokia 1600 unlocked
List your IMEI number
The country that it was made for
The provider it is locked to
list if the phone was purchased new or second hand. Also if you have tried any unlock codes, if you have, list the code that you have tried.
The guys on this website will post back your unlock code.
Again, DO NOT try any of the free calculaters listed, let them give you the code. They will give you the CORRECT unlock code normally within a couple of hours of you making the post so your phone will be sim free. be sure to follow up and post your results with a thank you