Ray Davison wrote:

Hey, it is wireless, and I couldn't find any place else to take the question.

When a cell phone is locked to a carrier, what is locked, the phone or the SIM.  I always thought it was the phone because they are sold as locked or unlocked.  If so, then what is this?
http://www.b2cshop24.com/en/turbo-sim-unlock-card-for-gsm-cell-mobile-no-need-to-cut.html I have several Motorola, GSM that I want to unlock from AT&T.  I own them.  And I have extra SIMs.  Is AT&T required to unlock them if I request?

Ray

Generally Cell providers will unlock phones from their network, often for a fee, if the phone is out of contract (i.e. you have paid off its value over a period of time, often 2 years). Whether AT&T are "forced" to do this for you may depend upon the contract that you signed with them.

I believe the "lock" is related to the phone itself, not the SIM as otherwise you could simply change the SIM and use the phone on another network - it may be that the SIM referred to at this site has an application on it to unlock phones. The legality of that and if after the action the phone will still work with the original or any carrier is a risk. Better to get the carrier to give you the unlock code if possible.