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Cell Phone Terms to Know
Last Updated: 01/13/2008
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Cell Phone Terms to Know
If you’ve ever researched cell phones to see which brand and carrier would be best for your needs, you know it can be confusing. Trying to figure out what if you want an unlocked cell phone or not, what MHz and frequency have to do with GSM or CDMA, or even what GSM and CDMA means can be a little intimidating. This is exactly why you want to know what they mean. If you know, you are empowered to buy the best phone possible. Knowing some common cell phone terms will help you choose a phone that is right for your needs.Digital – as opposed to analog – is how sound is transmitted. Your voice is translated into a binary code (series of 1’s and 0’s) and compressed, which allows between three and ten calls to occupy the same space one analog call would take. Each area is split up into cells, which allows millions of cell phone calls to take place simultaneously.
TDMA – Time Division Multiple Access – divides a radio frequency into time slots and then allocates slots to individual calls. Because of TDMA technology, a single frequency can support multiple, simultaneous usage. TDMA is used by the GSM network.
GSM – Global System for Mobile Communication – is a colossal network for cell phone users. Used throughout most of the world – with the notable exceptions of the US and Canada – GSM allows its subscribers to make and receive high quality phone calls, text messaging, and more within any area that is part of the GSM network. Mobile phones connect to the GSM network by searching for cells in the immediate area. GSM networks worldwide operate in the 900MHz or 1800MHz frequencies. The US has a few carriers who use GSM (AT&T, T-Mobile, and Cingular.) These use the 850MHz or 1900MHz frequencies. If your cell phone is going to be used in the US, an unlocked GSM cell phone is a great choice.
CDMA – Code Division Multiple Access – is a technology that allows more efficient use of the frequencies. Unlike TDMA, CDMA doesn’t assign a specific frequency to each user. Each channel uses the full available spectrum. To keep individual calls private, they are encoded. CDMA allows for more users to connect simultaneously. This is technology that was first used in World War II. Instead of transmitting over just one frequency, the US transmitted over several to prevent the Germans from picking up the complete signal. (CDMA phones do not use SIM cards – they are attached to one carrier. GSM, by contrast, allows unlocked cellular phone users to switch carriers and phones.
SIM Card – Subscriber Identity Module- is a portable chip that is inserted into GSM cell phones. A SIM card stores information on the subscriber (personal info, cell phone number, phone book, text messages, etc.) which allows the network service provider to recognize the user. In unlocked GSM phones, a SIM card can be used with another phone. If you want a new phone and it’s compatible, you can put your SIM card into the new phone. It retains your phone number and information and processes the calls as if it came from your previous phone. You can also use your SIM card in another person’s SIM-based phone and it uses your information, not the other person’s. Unlocked GMS phones allow users to switch service providers as well.
Locked cell phones have built-in capacity to restrict the use of phones to a particular country, network or service provider, or SIM type, which means the only certain SIM cards can be used with the phone. Locking a phone is legal and even required in some countries. Service providers can offer phones at deep discounts or even for free because you must buy the service plan. The phones are locked so you don’t get the free phone and then buy a service plan from another provider or insert another SIM card. Some locked phones are able to be unlocked after the service contract expires.
Unlocked cell phones are being sold more and more in the United States. They are GSM phones that can be used with compatible carriers throughout the world by simply inserting a SIM card. OEM unlocked cell phones come straight from the manufacturer (Nokia, Sony Ericsson, LG Mobile, etc.) and are not associated with any service provider at all. Carrier/Operator unlocked cell phones were originally locked for a specific provider and then unlocked. Unlocked cell phones make cell phone communication easier for people who travel internationally or who wish to change service providers with incurring fees and penalties. Having a basic knowledge of terms common to the cell phone industry can help you decide which type of phone to get. For instance, do you travel extensively? An unlocked GSM phone is a great option. If you like your current service provider and don’t plan to change, a locked phone will be fine for your needs. Make sure your phone and service off the best features for your needs.
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