This article is taken from here. Just want to share the info(s) =)
What does it mean when someone says their phone is "locked" or "unlocked"?
In the United States, as well as other countries, the cellular providers (AT&T, T-Mobile, Verizon, Sprint, etc.) make deals with the manufacturers (Apple, Samsung, Motorola, etc) to lock their phones to one particular network. Essentially what this means is that a phone you buy from AT&T, won't work on T-Mobile's network and visa versa. All GSM phones can be unlocked by entering special codes into the phone. Once unlocked, a GSM phone can work on any GSM network anywhere in the world by simply swapping out the SIM card.
CDMA phones cannot be unlocked due to the fact that they do not accept SIM cards and need to be programmed to a specific network in order to be used.
In the United States, as well as other countries, the cellular providers (AT&T, T-Mobile, Verizon, Sprint, etc.) make deals with the manufacturers (Apple, Samsung, Motorola, etc) to lock their phones to one particular network. Essentially what this means is that a phone you buy from AT&T, won't work on T-Mobile's network and visa versa. All GSM phones can be unlocked by entering special codes into the phone. Once unlocked, a GSM phone can work on any GSM network anywhere in the world by simply swapping out the SIM card.
CDMA phones cannot be unlocked due to the fact that they do not accept SIM cards and need to be programmed to a specific network in order to be used.
Why do cell phone carriers lock their phones in the first place?
The major cell phone carriers in the US lock their phones to their network because they want you to subscribe to a long term contract. An easy way to do this is to try and make it so your phone will only work on their network. The cell phone carriers make most of their money on their rate plans, not on the sale of phones.
Why is an unlocked phone more expensive than the exact same model phone sold through a cell phone carrier?
This ties in directly with the above question. In order to give customers an incentive to sign a long term contract, they subsidize the cost of the phone. While a cell phone carrier may offer you a phone at several hundred dollars off, in order to enjoy that discount, often times you need to commit to a 2 year contract. Even at the cheapest rate plan, that can often times add up to well over $1000 over the life of the contract. That's how the cell phone companies can afford to sell phones at such discounted prices. That's also a major reason why US cell phone customers on average have the second highest monthly rate plan charges in the world.
Because unlocked cell phones are sold as no contract phones and don't require any sort of commitment, they aren't subsidized and are offered at the actual retail prices.
What are the benefits of an unlocked cell phone - There are numerous reasons why someone might choose an unlocked cell phone over another phone. Here are just a few.
- Freedom of Choice - An unlocked phone gives you the customer the freedom to pick and choose which provider you want. You aren't bound by contracts that lock you to one provider, especially if you aren't happy with the customer service or coverage in your particular area. With an unlocked phone you can switch carriers without having to switch phones.
- For Travel Abroad - An unlocked phone is great for someone who travels a lot. While most carriers provide some sort of roaming capabilities, the charges can be astronomical. With an unlocked phone, you can simply buy prepaid SIM cards while abroad and use them in your handset.
- If you move a lot - While coverage maps are all the rage, there are areas of the country where some carriers have better signal strength than others. If you are compelled to switch providers in order to get a better signal, you can avoid the hassle of also having to buy a new phone.
- Selection - Because carriers only sell phones that are locked to their network, they offer a very limited selection of phones. There is a virtually unlimited supply of unlocked cell phones, from carriers around the world that will work on the various US GSM networks, meaning there is a better chance of you finding the phone that most ideally meets your needs.
When you purchase an unlocked phone certain settings may not work initially. For instance if you have a T-Mobile SIM card and you recently purchased an unlocked AT&T phone or vice versa, certain features such as multimedia messaging, text messaging, GPS, etc may not work right away. In order to rectify this you would need to contact your service provider and ask them for the APN (Access Point Name) settings for your phone. The APN defines the network path for all data services (Cellular Data, Visual Voicemail, MMS). Incorrect entries in the fields may disable the data services. To verify the proper APN information, please contact the carrier of the SIM card you are using. They should be able to provide you with information as well as explain how to change those settings on your phone.
*Please note- The above only applies if your carrier allows you to edit the APN settings.
Will this phone work internationally? Certainly, if your phone is compatible and your carrier allows it. Also, your phone needs to be either tri-band or quad-band capable in order to work internationally as the majority of GSM networks worldwide use three to four different frequencies within their network coverage area.
To use your phone abroad you must first check that your phone can operate on the frequency bands in use by your destination country. This information can be provided by calling your carrier. You may also need to make a request with your carrier to enable international roaming on your service plan.
When abroad your cell phone will be working on a foreign carrier which has an international roaming agreement with your home carrier. Any calls made or received abroad will normally be substantially higher than usual. Please consult your carrier for more information on your roaming call rates.
*Japan and South Korea operate exclusively on CDMA networks so and unlocked GSM phone will not be compatible in these countries.
