What is GSM mean and how is it different from CDMA?
First off, GSM stands for Global Systems for Mobile communications. It is a type of cell phone network first developed in Europe.
It is estimated that nearly 80% of the global cell phone community uses GSM networks. GSM technology operates on the four frequency
bands across the globe. These are 850/900/1800/1900 mhz. Each country uses a different combination of these four bands, usually a
maximum of two bands per country. The two frequency bands in use in the United States are 850 and 1900 mhz.
- The two major GSM carriers in the US are AT&T and T-Mobile. Currently, T-Mobile operates exclusively on the 1900 mhz band. AT&T operates on both the 850 and 1900 mhz band.
CDMA is another type of cell phone network. It is essentially a digital radio system that allows phones to access the same frequencies
at the same time. CDMA devices can only access frequencies that they have been programmed to access, significantly limiting roaming capabilities.
- The major CDMA carriers in the US are Verizon, Sprint, Metro PCS and US Cellular. Each operates on their own frequency.
GSM networks are designed to share signals, allowing for roaming agreements between different carriers around the world. GSM phones all use SIM
cards (Subscriber Identity Module), which can be removed from any phone and placed into any other GSM based phone.
As most GSM tri-band phones are models designed for maximum compatibility across the world, the most common combination of frequency bands in a
tri-band phone is 900/1800/1900 mhz. This means that if you travelled into an area which only has coverage on the 850 mhz band, you would be
unable to make or receive calls. However, manufacturers are now releasing tri-band phones optimized for the American market, which support the
850/1800/1900 frequency bands. This enables users to have maximum compatibility in the United States as well as being able to use the phone abroad.
Please check the frequency bands in the product descriptions to see which bands are supported.
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.
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.
Why do some functions not work on my unlocked cell phone?
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.
How should I charge my battery for the first time?
When you first receive your phone you should insert your battery only (not your SIM card for GSM phones) and charge it fully. It is recommended that
you "condition" your battery for the first 3 charging cycles. To do this, charge your battery fully and allow it to nearly drain completely before
charging it again. By conditioning your battery it will help ensure that you are using the full capacity of your battery for optimal performance.
Please note that before receiving an initial charge, a new battery may not power up the phone, or the phone/charger may not immediately show any charge
indicators, or the battery may prematurely (falsely) show a full charge. If you experience any of these conditions, continue to charge the battery for
an extended period of time (up to 12 hours).
How do I activate my Phone?
- T-Mobile - The first thing you should do is follow the instructions on how to properly charge your battery for your new phone. Then turn off your old phone and remove your SIM card. Make sure the power is off on your new phone and insert your SIM card. DO NOT USE THE SIM CARD THAT COMES WITH YOUR NEW PHONE. You're phone should be ready to go. There is a chance that some features on your new unlocked phone might not work right away and you'll need an APN. The process for this is easy and is explained later in this FAQ.
- AT&T - The first thing you should do is follow the instructions on how to properly charge your battery for your new phone. Then turn off your old phone and remove your SIM card. Make sure the power is off on your new phone and insert your SIM card. Power up your phone and you should be ready to go. There is a chance that some features on your new unlocked phone might not work right away and you'll need an APN. The process for this is easy and is explained later in this FAQ.
- Verizon - The first thing you should do is follow the instructions on how to properly charge your battery for your new phone. Then you simply need to call Verizon's customer service at 1-800-922-0204 and they will walk you through the activation process.
- Sprint - The first thing you should do is follow the instructions on how to properly charge your battery for your new phone. Then you simply need to call Sprint Customer service at 1-888-211-4727 and they will walk you through the activation process.