Unlock iPhone Features with Secret Codes
The iPhone has been on the market since 2007, yet there are still secrets many people don't know about.
If you're a developer or die-hard iPhone user, chances are you've known about these codes for a while. For the rest of us, inputting these codes into your iPhone's dialer might make for a neat party trick. I don't know how useful these settings are for daily use, but they're there in case you ever want to open a "field mode" on your device. Why not?