Unlocked AT&T iPhone - Is there anyway to tell outside of iTunes

[Wicked1]

I unlocked my old iPhone 4 thru AT&T, when connected to iTunes, it states it is unlocked when you first connect it, but is there a way to prove to someone when I sell it that it is unlocked?

 

[andyx3x]

Dial #227# and the screen will go black and the words "unlocked" will pop up on the screen.

 

[lapeno]

put your imei on this site :

http://www.dev.mk/

 

[Daveoc64]

Get a SIM from a different carrier and put it in the device.

Really, anything other than that doesn't prove anything.

 

[lapeno]

Get a SIM from a different carrier and put it in the device.

Really, anything other than that doesn't prove anything.

The phone could have ultrasnow installed