What Do All Those Unlocked Cell Phone Terms Mean?
If you're considering buying an unlocked cell phone, you've probably already run into terms like SIM, GSM, and quad-band.
This lens is here to give you simple definitions of the terms you'll run into when shopping for an unlocked phone.
I'm not going to go into the technology behind all this stuff. You don't need to know it to successfully select and buy an unlocked cell phone. If you're smart enough to be thinking about buying an unlocked phone, you can easily understand anything you'll find here.
Dual Band
A dual-band phone is one that operates on only one of the common pairs of GSM frequency bands. What this means for you is that a dual band phone made for the US market will not usually work in Europe or Asia, and vice versa, since those parts of the world use different pairs of frequency bands.
Frequency Band
While GSM phones all use the same basic technology, they may operate on various frequency bands. Each band is a section of the radio spectrum reserved for use by GSM phones. Four bands are in common use today.
GSM-850 and GSM-1900 are used primarily in the United States and the rest of the Americas.
GSM-900 and GSM-1800 are used in most of the rest of the world.
You may see the bands described in different formats. For example, GSM-850 is also described as GSM 850, and GSM 850 MHz.
The most important thing to remember about frequency bands is that you want to buy a phone that works on both the frequency bands as the country you will be using it in. So if you live in the United States, make sure any phone you buy works with both GSM-850 and GSM-1900.
GSM-850 and GSM-1900 are used primarily in the United States and the rest of the Americas.
GSM-900 and GSM-1800 are used in most of the rest of the world.
You may see the bands described in different formats. For example, GSM-850 is also described as GSM 850, and GSM 850 MHz.
The most important thing to remember about frequency bands is that you want to buy a phone that works on both the frequency bands as the country you will be using it in. So if you live in the United States, make sure any phone you buy works with both GSM-850 and GSM-1900.
GSM (Global System for Mobile communications)
GSM, which stands for Global System for Mobile communications, is the most commonly used standard for cell phones in the world. It is also the standard that unlocked cell phones work with.
In the United States, AT&T and T-Mobile are the cellular carriers that use the GSM standard. Verizon Wireless and other US carriers use different standards and don't work with unlocked phones.
For more information on this technology, see this GSM article on Wikipedia.
In the United States, AT&T and T-Mobile are the cellular carriers that use the GSM standard. Verizon Wireless and other US carriers use different standards and don't work with unlocked phones.
For more information on this technology, see this GSM article on Wikipedia.
Quad Band
A quad-band phone is one that works with both pairs of commonly used GSM frequency bands. This means that a quad band phone can be used anywhere in the world that GSM phone service is available.
Quad band phones are also often referred to as world phones.
Quad band phones are also often referred to as world phones.
SIM (Subscriber Identity Module)
A SIM (Subscriber Identity Module) stores information that identifies a cell phone and allows it to work on a particular network. All GSM phones use SIMS, which take the form of tiny cards containing a microprocessor and a bit of memory.
When you are using an unlocked cell phone, changing the SIM allows the phone to work on a different network.
SIMs are usually referred to as SIM cards.
When you are using an unlocked cell phone, changing the SIM allows the phone to work on a different network.
SIMs are usually referred to as SIM cards.
Tri Band
A tri-band phone is one that is designed to be used primarily in one part of the world, with some ability to work elsewhere.
A tri-band phone you buy from one of the US carriers will support both of the GSM frequency bands in use in North America, and one of the bands used in the rest of the world. In practice, this means that a tri-band phone made for the US market will usually work in Europe or Asia, depending on exactly where you are at the time, which cell towers are in range, and so on.
A tri-band phone you buy from one of the US carriers will support both of the GSM frequency bands in use in North America, and one of the bands used in the rest of the world. In practice, this means that a tri-band phone made for the US market will usually work in Europe or Asia, depending on exactly where you are at the time, which cell towers are in range, and so on.
What unlocked cell phone terms do you need help with?
In this lens I've tried to cover the terms and acronyms you're most likely to run into when shopping for an unlocked phone. Did I miss any? Is there a term you think I should add to this lens? If so, let me know here.
Thanks.
--Bill
Related Unlocked Cell Phone Lenses
Here are links to other lenses I've published on unlocked cell phones. Between them, they tell you everything you need to know about buying and using unlocked phones.
- My Unlocked Cell Phone Home Lens
- This lens is the hub for my set of lenses on unlocked cell phones. It's a great place to start learning (or shopping!) and the place I recommend you go first when you've finished checking out this lens.
