What does "unlocked" mean when referring to a cell phone?

February 2, 2005 6:26 AM

Cell phone(s): Can anyone tell me what "unlocked" means when referring to a cell phone? I see this on eBay quite a bit.
posted by johnj to Technology (8 answers total)

Cell phones are manufactured "unlocked", as it were, but most cell phone service providers electronically lock the phone so that it can only be used with their service, to keep you from changing providers. The phones can be unlocked again with a special code. More here.
posted by iconomy at 6:35 AM on February 2, 2005

It refers to GSM phones (ones that use SIM cards) that can be used on any network within its frequency. Often times major carriers lock phones to offset the cost of reducing their prices on cell phones (see free phones). Almost every GSM phone can be unlocked; some require cables, codes, flashing, etc.
posted by BlueTrain at 6:35 AM on February 2, 2005

Response by poster: Thanks.
So, if I understand correctly, I can use any unlocked phone that is set up correctly for any cell service.

hmmmmm
posted by johnj at 6:45 AM on February 2, 2005

Not exactly. Certain phones use certain bands. All originally US phones can be used in the US (if I'm not mistaken; someone jump in here if I'm wrong); but if you plan to travel abroad, look into either a tri-band or quad-band phone.
posted by BlueTrain at 6:47 AM on February 2, 2005

I had a response, but on preview iconomy said essentially the same thing.

However an important point. I'm assuming from your profile that you're in the United States. In the United States, there are different cell phone technologies. Cingular and T-Mobile are primarily GSM (a technology prevalent in Europe)
Verizon and Sprint are primarily CDMA (a technology strong in North America and parts of Asia)
Nextel has its own technology called iDEN.

A GSM phone will not work on any other technology other than GSM. For example, you can't buy a GSM phone and have it work on Sprint or Verizon. So be sure to take technology into account if you make any purchases.
posted by forforf at 6:53 AM on February 2, 2005

Also, in the US there are two GSM bands that are used: 850 MHz and 1900 MHz. Near as I can tell, T-Mobile uses just 1900 MHz while Cingular uses both. So if you want maximum flexibility, make sure any GSM phone you buy, if you want to unlock it, can do both. As BlueTrain says, there are also two international bands 900 MHz and 1800MHz that are used by different providers.
posted by skynxnex at 7:07 AM on February 2, 2005

Note that to use an unlocked GSM phone on another service, you have to remove your provider's SIM card (it's usually kept under the phone's battery) and replace it with one for the other service you wish to use. I've heard of some phones designed for world travellers having multiple SIM slots, and SIM adapters that allowed you to connect multiple SIM cards and select them by "dialing" special numbers.

I believe that all phones Cingular sells as "world phones" are already unlocked. The LG I got from them works at 850, 1900, and 1800MHz and came unlocked.
posted by zsazsa at 7:32 AM on February 2, 2005

So, if I understand correctly, I can use any unlocked phone that is set up correctly for any cell service.

Or, put another way, any unlocked phone will work with your phone service -- as long as that phone supports the frequencies which your provider uses.
posted by Handcoding at 1:45 PM on February 2, 2005