Can anyone tell me how to "Unlock" a cell phone?

[babsbunny]

This may not be the correct forum but I switched cell phone companies, got a new crappy phone and miss my old good phone. I put the SIM card from my new crappy phone into my old good phone and it says I need a code to unlock my good phone. Anyone know what that code is or how to fix this?

[ChromeFoundry]

1. You'll need to specify

The old and new cell carriers (this is to determine if they use compatible bands - CDMA or GSM) and the type of phone, including model that you are attempting to unlock (Apple iPhone 4s, HTC Incredible S S710E... etc).

[babsbunny]

2. The old carrier was T-Mobile

The cell phone was a Dash 3G HTC, this is the one I need unlocked, the new carrier is Consumer cellular where I got a crappy phone.

[PowerToThePeople]

3. Call t-mobile

I use t-mobile, but have purchased second hand at&t phones before.

If the phone is not still under contract, they should be able to give you the codes to 'carrier unlock' it.

[babsbunny]

4. Thanks!

[Old Codger]

7. Some will

Some won't but if not you can go to Amazon and search on "unlocked" cell phones and find some pretty decent ones at ok prices....I use an unlocked S3 and have 2 others different ones that I bought there that work with consumer cellular ok,as does the S3

[backscatter712]

6. What kind of phone do you have?

Each model of phone has its own unlock procedure.